You have to isolate x. First you start off by adding the like terms which is -3x and -x. By adding them you get -4x.
8 - 4x = 12
Then you subtract 8 on both sides since it is positive to isolate x.
-4x = 4
Then you divide -4 by both sides and get x=4/-4
4/-4 is simplified to -1 so the answer is x= -1
Equation C. :) lalalalalala
The diagram shows that all the sides of the rectangle are congruent. Since the perimeter all of the sides added up, all you have to do is divide the perimeter by 4.
Therefore, the perimeter, which is 16x + 24, can be divided by 4 to find the length of one side.
16x + 24/4 = length of one side. So, the length of one side is 4x + 6.
Hope this helped!
I'm not exactly sure what you're asking but <em />I'll give it a go.
A = x -6