SOLUTION: how do solve base and height trianlges? the question:the base of a triangle is 9cm greater than the height. the area is 56cm^2.Find the base and height. my answer:b=h+9

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Question 21295: how do solve base and height trianlges?
the question:the base of a triangle is 9cm greater than the height. the area is 56cm^2.Find the base and height.
my answer:b=h+9
A=56cm^2
56=(h+9)h
0=h^2+9h-56
then thats where i get stuck can you help please.
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
You forgot the "1/2" in the area formula.
Area = (1/2)(base)(height)
56 = (1/2)(h+9)(h)
112 = h^2+9h
h^2+9h-112=0
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 1x%5E2%2B9x%2B-112+=+0) has the following solutons:

x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca

For these solutions to exist, the discriminant b%5E2-4ac should not be a negative number.

First, we need to compute the discriminant b%5E2-4ac: b%5E2-4ac=%289%29%5E2-4%2A1%2A-112=529.

Discriminant d=529 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28-9%2B-sqrt%28+529+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%289%29%2Bsqrt%28+529+%29%29%2F2%5C1+=+7
x%5B2%5D+=+%28-%289%29-sqrt%28+529+%29%29%2F2%5C1+=+-16

Quadratic expression 1x%5E2%2B9x%2B-112 can be factored:
1x%5E2%2B9x%2B-112+=+1%28x-7%29%2A%28x--16%29
Again, the answer is: 7, -16. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+1%2Ax%5E2%2B9%2Ax%2B-112+%29