Here is the answer from SparkNotes
http://www.sparknotes.com/math/algebra2/operationsonfunctions/section3.rhtml
A) Height -7 = base
B) .5 * height * base = 60
Substituting A into B
B) .5 * height * (height -7) = 60
B) .5*height^2 -3.5*height = 60
B) .5*height^2 -3.5*height -60 = 0
Using the quadratic formula:
Height = 15
Subtracting 7 gives us the base length
Base = 8
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Double-Check
.5 * 15 * 8 = 60
4x-2+1=3x+5
Subtract 3x from both sides
x-2+1=5
Same as
x-1=5
Add 1 to both sides
x=6
Well there’s two sides of a coin
so divide 58 by 2 to get 29
