Question

solve for input of function given output
question
given $f(x) = -x - 5$, solve for $x$ when $f(x) = 4$.

Explanation:

Step1: Substitute \( f(x) \) with 4

We know that \( f(x) = -x - 5 \) and \( f(x) = 4 \), so we substitute to get \( 4 = -x - 5 \).

Step2: Solve for \( x \)

Add 5 to both sides: \( 4 + 5 = -x - 5 + 5 \), which simplifies to \( 9 = -x \).
Multiply both sides by -1: \( -9 = x \), so \( x = -9 \).

Answer:

\( x = -9 \)