1. Square:
There are 4 equal sides of a square, so Perimeter = side length * 4
Perimeter expression - (4)10x
The perimeter of the square is 40x
2. Rectangle:
There are 4 unequal sides of a rectangle, so Perimeter = 2l + 2w
Length: 2x+7
Width: 3x+8y
Perimeter expression - 2(2x+7) + 2 (3x+8y)
(2x+7) *2 = 4x + 14
(3x+8y) *2 = 6x+16y
(4x +14) + (6x + 16y)
4x+6x +16y+14
The perimeter of the rectangle is 10x + 16y + 14