The length of a rectangular poster is 7 inches more than twice its width. find the length of the poster if its perimeter is 110 inches.

Let W = width of poster 
Since the length is 7 inches longer than the width, the length is represented by W + 7. 
We know the perimeter is equal to twice the length + twice the width and that is 110 inches. Mathematically that looks like: 
2(W + 7) + 2(W) = 110
Now let's solve for W: 

2(w+7)+2w=110

Step 1: Simplify both sides of the equation.

2(w+7)+2w=110

Simplify: (see simplify steps down below)

4w+14=110

Step 2: Subtract 14 from both sides.

4w+14−14=110−14

4w=96

Step 3: Divide both sides by 4.

4w4=964

w=24

w=24

Simplify Steps:
(2)(w)+(2)(7)+2w=110(Distribute)

2w+14+2w=110

(2w+2w)+(14)=110(Combine Like Terms)

4w+14=110