Respuesta :

Hello from MrBillDoesMath!

Answer:

x = 5



Discussion:

Perimeter = 78

Perimeter = sum of lengths of 4 sides =

                 = 2 (2x +4) + 2(5x)

=>

2(2x+4) + 2(5x) = 78 =>

4x + 8 + 10x = 78 =>

14x + 8 = 78 =>

14x = 78 -8 = 70 =>

x = 70/14 = 5


Thank you,

MrB