Answer:
x =
or 
Step-by-step explanation:
The area of a trapezoid is:

A = area
a = base 1
b = base 2
h = height
Area = unknown
base 1 = 2.5
base 2 = 7.5
height = 2.5
^^^Plug these numbers into the formula!

A = (10/2)(2.5)
A = (5)(2.5)
A = 12.5
Hope this helped!
Do you want a whole number or a fraction?
What you need to do is do the inverse operation on both sides. So right now, 8 is being multiplied by h, so the inverse operation is division. You divide by 8 on both sides to get what h equals. So your equation looks like:
8h/8=112/8
8h/8 cancels out, so you are left only with h. 112 divided by 8 is 14, so your left with h=14 and that is your answer.