Bluebook SAT Test Linear Functions 10

Question 1

A candle is 18 cm tall and burns at 0.6 cm per minute. The function h(t) = 18 − 0.6t models its height. After how many minutes will it be 7.2 cm tall?

Accepted Answer

18

Answer

18 − 0.6t = 7.2 → 0.6t = 10.8 → t = 18.

Question 2

Line r is perpendicular to y = (3/4)x − 2. Which equation could represent line r?

Accepted Answer

y = −(4/3)x + 5

Answer

The perpendicular slope is the negative reciprocal of 3/4, which is −4/3; y = −(4/3)x + 5 has that slope.

Question 3

If g(x) = −3x + 7, for what value of x does g(x) = g(−1)?

Accepted Answer

−1

Answer

g(−1) = −3(−1) + 7 = 10; g(x) = 10 → −3x + 7 = 10 → −3x = 3 → x = −1. The function value g(−1) equals itself only at x = −1.

Question 4

Two lines intersect at (3, 5). One line has equation y = x + 2. Which of the following could be the other line's equation?

Accepted Answer

y = −2x + 11

Answer

Check: −2(3) + 11 = −6 + 11 = 5 ✓; (3, 5) lies on y = −2x + 11.

Question 5

What does the x-intercept of a linear function represent in a context where y is profit (in dollars) and x is units sold?

Accepted Answer

The break-even point — the number of units where profit equals zero

Answer

The x-intercept is where profit y = 0, meaning the number of units at which the business neither gains nor loses money — the break-even point.

Bluebook SAT Practice Test

Bluebook SAT Practice Test

Bluebook SAT Test Linear Functions 10