Answer:
x = 3
Step-by-step explanation:
Rectangle = length*width = 3(x+12) = 3x+36
Triangle = length*width/2 = 2x*5/2 = 5x
Since the rectangle is 3 times the triangle, thjat gives us:
3x+36 = 3(5x) -> 3x + 36 = 15x
Isolate x and solve:
36 = 12x
x = 3
