Week 7 Quiz

Written in standard form ax² + bx + c = 0, the week's parabola equation is x² − 6x + 5 = 0. What are a, b, and c?

Select one.

• a = 1, b = −6, c = 5
• a = 1, b = 6, c = 5
• a = 0, b = −6, c = 5
• a = 2, b = −6, c = 5

Solve x² − 5x + 6 = 0 by factoring.

Select one.

• (x + 2)(x + 3) = 0, so x = −2 or x = −3
• (x − 1)(x − 6) = 0, so x = 1 or x = 6
• (x − 2)(x − 3) = 0, so x = 2 or x = 3
• (x − 2)(x − 3) = 0, so x = −2 or x = −3

An object's height in feet t seconds after launch is h(t) = −16t² + 64t + 80. Setting the height to 0 gives −16t² + 64t + 80 = 0, which factors to (t − 5)(t + 1) = 0 after dividing by −16. When does the object land?

Select one.

• At t = 2 seconds
• At t = 5 seconds
• At t = −1 seconds
• At both t = 5 seconds and t = −1 seconds

Which first step solves 3x² − 12x = 0 without losing an answer?

Select one.

• Divide both sides by 3x to get x − 4 = 0
• Divide both sides by 3 and stop at x² = 4x
• Add 12x to both sides, then divide by x
• Factor out 3x to get 3x(x − 4) = 0

Select every value of x that solves x² = 7x.

Select every option that applies.

• 0
• 7
• −7
• 49

Solve (x − 3)² = 16 with the square root property.

Select one.

• x = 7 only
• x = 7 or x = −1
• x = 19 or x = −13
• x = −7 or x = 1

You complete the square on x² − 6x + 5 = 0 by moving the 5, taking half of −6, squaring it, and adding the square to both sides. Which equation results?

Select one.

• (x − 3)² = 4
• (x − 3)² = −5
• (x − 6)² = 31
• (x + 3)² = 4

Solve x² − 4x + 1 = 0 with the quadratic formula, and give the exact answer.

Select one.

• x = −2 ± √3
• x = 4 ± √3
• x = 2 ± √3
• x = 2 ± √12

What is the discriminant of 2x² − 4x + 2 = 0, and what does it predict?

Select one.

• 16, so two real solutions
• −16, so no real solution
• 0, so no real solution
• 0, so one repeated solution

The equation x² + 2x + 5 = 0 has no real solution, because its discriminant, 2² − 4(1)(5) = 4 − 20 = −16, is negative.

True or false.

• True
• False