Question

F(x) = -x² - 8x - 16; Find ƒ(-3)

Answer 1

f(-3) = -1

Explanation:

We can find an unknown y-value by plugging an x-value into a given function.

Function Notation

Before we answer this question, we need to understand the notation of the equation. In function notation, the equation is given in terms of f(x).

• "f(x)" represents the y-value of a function at the point "x".

For example, f(-3) represents the value of y when x = -3.

Finding f(3)

As stated above, to find f(-3) we need to plug -3 in for x. *Remember to use PEMDAS when solving.* This creates the new equation:

• f(-3) = -(-3)² - 8(-3) - 16

Then, distribute the exponent.

• f(-3) = -9 - 8(-3) - 16

Next, multiply.

• f(-3) = -9 - (-24) - 16

Distribute the negative.

• f(-3) = -9 + 24 - 16

Finally, add the remaining terms.

• f(-3) = -1

This means that when x = -3, y or f(-3) = -1.