Question

A function follows the rule y = -75 - 5x. When the function's output is 25, the equation is 25 = -75 - 5x.

What is the function input when the output is 25?

20
-10
-20
10

Answer 1

To find the function input \( x \) when the output \( y \) is 25, we can set up the equation based on the given function:

\[
25 = -75 - 5x
\]

Now, we'll solve for \( x \).

1. Add 75 to both sides of the equation:

\[
25 + 75 = -5x
\]

This simplifies to:

\[
100 = -5x
\]

2. Next, divide both sides by -5:

\[
x = \frac{100}{-5}
\]

This simplifies to:

\[
x = -20
\]

So, the function input when the output is 25 is \( \boxed{-20} \).