The perimeter of a rectangle is 42 cm. The longer side has length of 7 cm more than the shorter side. Find the length of longer side

To find perimeter, we use this equation.

2L+2W=42

Let's say the longer side is the length.

L=W+7

Let's plug that in for L.

2 (w+7) + 2w=42

2w+14+2w=42

Add like terms.

4w+14=42

Subtract 14 from both sides.

4w=28

Divide.

28:4=7=W

The shorter side is 7, which means the longer side is 14 cm.

So to solve, make an equation (x being the shorter side)

2x+2 (7+x) = 42

So just solve from here.

2x + 14 + 2x = 42

4x=28

x=7

So the shorter side is 7, and the longer side is 14.