Answer:
Try photo math, it will explain it all to you
The volume is V=LxWxH. The length x Width is just the area, A, of the bottom (also of the top) So you could also write V=AxH, that is volume is
area x height. Since we know V equals 972 and A equals 81 we can solve for H:
V=AxH
972=81H
972/81=H
H=12cm
The solution set is basically when are they equal. to figure this out we must set them equal. So so we will move some stuff around
x+y=5
y=5-x
y=x^2-25
we know that when they are equal their x and y values are equal. So so we know that their y values are the same so we can say:
y=y
this does not direarly help but looking above we know what both of the y's equal. so:
5-x = x^2-25
we want to set this equal to zero
0 = x^2 +x - 30
now we factor
0 = (x + 6) * (x - 5)
the only way to multiply 2 things together and get zero is for one of those things to equal 0. So so we know that to be zero one of the answers in parenthesis has to equal 0. so:
0 = (x + 6 =0) * (x - 5=0)
So now we solve for both parenthesis
x+6=0
x=-6
x-5=0
x=5
x=-6,5