Question

9 evaluate: f(x)=-8x-9; find f(-3)
10 evaluate: f(x) = 3(-2x + 7); find f(2)
11 evaluate: f(x) =-4(x +3) -14; find f(-4)
12 evaluate: f(x) =-x-11; find f(-8)

Explanation:

Problem 9:

Step1: Substitute \( x = -3 \) into \( f(x) \)

Given \( f(x) = -8x - 9 \), replace \( x \) with \( -3 \): \( f(-3) = -8(-3) - 9 \)

Step2: Calculate the expression

First, \( -8(-3) = 24 \), then \( 24 - 9 = 15 \)

Step1: Substitute \( x = 2 \) into \( f(x) \)

Given \( f(x) = 3(-2x + 7) \), replace \( x \) with \( 2 \): \( f(2) = 3(-2(2) + 7) \)

Step2: Simplify inside the parentheses

\( -2(2) = -4 \), so \( -4 + 7 = 3 \)

Step3: Multiply by 3

\( 3 \times 3 = 9 \)

Step1: Substitute \( x = -4 \) into \( f(x) \)

Given \( f(x) = -4(x + 3) - 14 \), replace \( x \) with \( -4 \): \( f(-4) = -4(-4 + 3) - 14 \)

Step2: Simplify inside the parentheses

\( -4 + 3 = -1 \)

Step3: Multiply by -4

\( -4(-1) = 4 \)

Step4: Subtract 14

\( 4 - 14 = -10 \)

Answer:

\( 15 \)

Problem 10: