### Home > CALC > Chapter 8 > Lesson 8.3.1 > Problem8-106

8-106.

Multiple Choice: If $y = 3x − 12$, then the minimum product for $xy$ is:

1. $3$

1. $0$

1. $−9$

1. $−12$

1. $−18$

Before using Calculus, write an equation with only one variable. Let $f(x) = xy$. Then use $y = 3x − 12$ to solve write $f(x)$ in terms of $x$ only.

Optimize. Remember that you are looking for the minimum product, not the minimum value of $x$.