The perimeter of a rectangle is 220 inches. The ratio of the length to width is 7:3. Find
the length and width.

Hey there!

Functions are basically like machines you put a number into and they give you a new one as an output. This f represents this machine. f(x) represents whatever the output is because it is the x after it has gone through the function machine.

We want to figure out what x is when f(x)=12. Well, we can simply replace f(x) with 12 in the first equation and solve for x!

12=-16x+8

We flip the equation so x is on the left side.

-16x+8=12

We subtract 8 from both sides.

-16x=4

We divide both sides by -16.

x=-1/4

Have a wonderful day! :D