Answer:
Step-by-step explanation:
Perimeter is all sides added together.
l is length, w is width, and P is perimeter.
[tex]2l + 2w = P\\2(5x) + 2(x - 3) = 42\\10x + 2x - 6 = 42\\12x - 6 = 42\\12x = 48\\x = 4[/tex]
