### Home > A2C > Chapter 1 > Lesson 1.1.1 > Problem 1-4

1-4.

"Find " means to find the output of function

*for an input of*

*. For the function*

Find

. (This means find the output of the function when.)Substitute

for each .Simplify.

Find

when. (This means find the input that gives an output of.) Substitute

for .Solve for

(multiply both sides by).