Hey don't cry . I'm not good at math either but try to take a deep breath.
The volume of a prism = area of the base * height
substitute:
640 = A * 8
base area=80 sq ft<span />
Step-by-step explanation:
3x-2x=5+10 [taking variables on one side and constant on other]
x=15
soln:
3x-5= 2x+10
3x -5+5=2x+10+5 [ adding 5 on both side]
3x=2x+15
3x-2x=2x+15-2x [subtracting 2x on both side]
x=15
Ans=15
