BackCollege Algebra Chapter 1 Test Review – Step-by-Step Guidance
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Q1. Find the sum: (2 - i) - (-3 + 5i)
Background
Topic: Complex Numbers – Addition and Subtraction
This question tests your ability to add and subtract complex numbers, combining real and imaginary parts.
Key Terms and Formulas:
Complex number: where is the real part and is the imaginary part.
Add/subtract: Combine real parts and imaginary parts separately.
Step-by-Step Guidance
Write both complex numbers: and .
Subtract the second from the first: .
Distribute the negative sign: .
Combine real parts: ; combine imaginary parts: .
Try solving on your own before revealing the answer!
Final Answer: 5 - 6i
We combined the real parts () and imaginary parts () to get .
Q2. Multiply: (-4 - 3i)(5 - 6i)
Background
Topic: Complex Numbers – Multiplication
This question tests your ability to multiply two complex numbers using the distributive property (FOIL method).
Key Terms and Formulas:
Complex number:
Multiplication:
Step-by-Step Guidance
Write both numbers: and .
Apply FOIL: Multiply each term in the first by each in the second.
Calculate: , , , .
Combine like terms and use to simplify.
Try solving on your own before revealing the answer!
Final Answer: -38 + 9i
After multiplying and simplifying, the result is .
Q3. Find the product of and its conjugate
Background
Topic: Complex Numbers – Conjugates
This question tests your understanding of multiplying a complex number by its conjugate.
Key Terms and Formulas:
Conjugate: If , then conjugate is .
Product:
Step-by-Step Guidance
Write the complex number: .
Write its conjugate: .
Multiply: .
Apply the formula: where , .
Try solving on your own before revealing the answer!
Final Answer: 1/4
Multiplying a complex number by its conjugate gives a real number: .
Q4. Divide:
Background
Topic: Complex Numbers – Division
This question tests your ability to divide complex numbers by rationalizing the denominator.
Key Terms and Formulas:
To divide by , multiply numerator and denominator by the conjugate .
Conjugate:
Formula:
Step-by-Step Guidance
Write the expression: .
Multiply numerator and denominator by the conjugate of the denominator: .
Calculate numerator: .
Calculate denominator: .
Try solving on your own before revealing the answer!
Final Answer:
After rationalizing, the result is .
Q5. Write in the form
Background
Topic: Complex Numbers – Square Roots of Negative Numbers
This question tests your ability to simplify square roots of negative numbers and write the result as a complex number.
Key Terms and Formulas:
Combine real and imaginary parts.
Step-by-Step Guidance
Simplify .
Simplify using .
Combine the results: real part and imaginary part.
Try solving on your own before revealing the answer!
Final Answer: -9 + 2i
We simplified to and to .
Q6. Write in the form
Background
Topic: Complex Numbers – Square Roots of Negative Numbers
This question tests your ability to simplify and write expressions involving square roots of negative numbers as complex numbers.
Key Terms and Formulas:
Combine real and imaginary parts.
Step-by-Step Guidance
Simplify (real part).
Simplify : , so .
Combine: .
Try solving on your own before revealing the answer!
Final Answer:
We simplified to and combined with .
Q7. Solve by factoring:
Background
Topic: Quadratic Equations – Factoring
This question tests your ability to solve quadratic equations by factoring.
Key Terms and Formulas:
Quadratic equation:
Factoring: Set each factor equal to zero.
Step-by-Step Guidance
Write the equation: .
Factor out : .
Set each factor equal to zero: or .
Try solving on your own before revealing the answer!
Final Answer: 0, 12
Setting each factor to zero gives the solutions and .
Q8. Solve by factoring:
Background
Topic: Quadratic Equations – Factoring
This question tests your ability to factor and solve quadratic equations.
Key Terms and Formulas:
Quadratic equation:
Factoring: Find two numbers that multiply to and add to .
Step-by-Step Guidance
Write the equation: .
Factor: Find two numbers that multiply to $15.
Write the factors: .
Set each factor equal to zero and solve for .
Try solving on your own before revealing the answer!
Final Answer: -3, -5
The factors are , so and .
Q9. Solve by factoring:
Background
Topic: Quadratic Equations – Factoring
This question tests your ability to rearrange and factor quadratic equations.
Key Terms and Formulas:
Quadratic equation:
Factoring: Rearranging and factoring.
Step-by-Step Guidance
Move all terms to one side: .
Factor the quadratic equation.
Set each factor equal to zero and solve for .
Try solving on your own before revealing the answer!
Final Answer:
Factoring and solving gives and .
Q10. Solve using the square root property:
Background
Topic: Quadratic Equations – Square Root Property
This question tests your ability to solve quadratic equations using the square root property.
Key Terms and Formulas:
Square root property: If , then .
Step-by-Step Guidance
Divide both sides by $4(x - 2)^2$.
Take the square root of both sides: .
Solve for by adding $2$ to both sides.
Try solving on your own before revealing the answer!
Final Answer:
Using the square root property, .
Q11. Solve by completing the square:
Background
Topic: Quadratic Equations – Completing the Square
This question tests your ability to solve quadratic equations by completing the square.
Key Terms and Formulas:
Completing the square:
Move constant to other side, add to both sides.
Step-by-Step Guidance
Move constant to other side: .
Add to both sides.
Write as a perfect square: .
Take the square root: .
Try solving on your own before revealing the answer!
Final Answer:
Completing the square gives .
Q12. Solve using the quadratic formula:
Background
Topic: Quadratic Equations – Quadratic Formula
This question tests your ability to use the quadratic formula to solve equations.
Key Terms and Formulas:
Quadratic formula:
Discriminant:
Step-by-Step Guidance
Identify , , .
Calculate discriminant: .
Plug values into quadratic formula.
Simplify under the square root and denominator.
Try solving on your own before revealing the answer!
Final Answer:
The discriminant is negative, so solutions are complex.
Q13. Use the discriminant to determine the number and nature of solutions for
Background
Topic: Quadratic Equations – Discriminant
This question tests your ability to use the discriminant to determine the nature of solutions.
Key Terms and Formulas:
Discriminant:
If discriminant , two real solutions; , one real solution; , two nonreal solutions.
Step-by-Step Guidance
Identify , , .
Calculate discriminant: .
Determine if discriminant is positive, zero, or negative.
Try solving on your own before revealing the answer!
Final Answer: Discriminant = 52; two real solutions
Since the discriminant is positive, there are two real solutions.
Q14. The sum of the square of a positive number and the square of 3 more than the number is 149. What is the number?
Background
Topic: Quadratic Equations – Word Problems
This question tests your ability to translate a word problem into a quadratic equation and solve it.
Key Terms and Formulas:
Let be the positive number.
Equation:
Step-by-Step Guidance
Let be the positive number.
Write the equation: .
Expand .
Combine like terms and solve the quadratic equation.
Try solving on your own before revealing the answer!
Final Answer: 7
Solving the quadratic equation gives .
Q15. Benjamin threw a rock from a cliff 36 ft above water. Height after seconds: . How long until it hits the water?
Background
Topic: Quadratic Equations – Applications
This question tests your ability to solve a quadratic equation in a real-world context.
Key Terms and Formulas:
Set to find when the rock hits the water.
Equation:
Step-by-Step Guidance
Set and write the equation: .
Solve the quadratic equation for using factoring or quadratic formula.
Choose the positive value for (time cannot be negative).
Try solving on your own before revealing the answer!
Final Answer: 3 seconds
The positive solution for is 3 seconds.
Q16. A kite is flying on 106 ft of string. Its height is 34 ft more than the horizontal distance from the person. How high is it?
Background
Topic: Quadratic Equations – Applications
This question tests your ability to set up and solve a right triangle problem using the Pythagorean theorem.
Key Terms and Formulas:
Let be the horizontal distance.
Height:
Pythagorean theorem:
Step-by-Step Guidance
Let be the horizontal distance; height is .
Write the equation: .
Expand and solve for .
Find the height: .
Try solving on your own before revealing the answer!
Final Answer: 90 ft
Solving gives the height as 90 ft above the ground.
Q17. Find all solutions:
Background
Topic: Polynomial Equations – Cubic Equations
This question tests your ability to solve cubic equations by factoring.
Key Terms and Formulas:
Move all terms to one side:
Factor the cubic equation.
Step-by-Step Guidance
Move all terms to one side: .
Factor the cubic equation (try rational root theorem or grouping).
Set each factor equal to zero and solve for .
Try solving on your own before revealing the answer!
Final Answer: -5, 0, 1/3
Factoring gives three solutions: .
Q18. Solve the radical equation:
Background
Topic: Radical Equations
This question tests your ability to solve equations involving square roots.
Key Terms and Formulas:
Set the radicand equal to zero:
Step-by-Step Guidance
Set .
Square both sides to eliminate the radical.
Solve for .
Try solving on your own before revealing the answer!
Final Answer: 1
Solving gives .
Q19. Solve the polynomial inequality:
Background
Topic: Polynomial Inequalities
This question tests your ability to solve polynomial inequalities and express the solution in interval notation.
Key Terms and Formulas:
Move all terms to one side:
Factor and solve the inequality.
Step-by-Step Guidance
Move all terms to one side: .
Factor the expression.
Find critical points and test intervals.
Express the solution in interval notation.
Try solving on your own before revealing the answer!
Final Answer: (2, 6)
The solution in interval notation is .
Q20. Solve the rational inequality:
Background
Topic: Rational Inequalities
This question tests your ability to solve rational inequalities and express the solution in interval notation.
Key Terms and Formulas:
Find zeros of numerator and denominator.
Test intervals between critical points.
Express solution in interval notation.
Step-by-Step Guidance
Set numerator and denominator to find critical points.
Test values in each interval to see where the inequality holds.
Include endpoints as appropriate.
Try solving on your own before revealing the answer!
Final Answer: [ -2, 5 )
The solution in interval notation is .