SOLUTION: Write and solve a quadratic equation. A right triangle has a hypotenuse of 105 inches. One leg is forty-two inches less than double the other leg. What is the length of the shorter

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Question 1060594: Write and solve a quadratic equation. A right triangle has a hypotenuse of 105 inches. One leg is forty-two inches less than double the other leg. What is the length of the shorter leg? (Hint: a^2+b^2=c^2)
I just need help with this question. If you could show step by step that would be perfect thanks!

Answer by MathTherapy(10551) About Me  (Show Source):
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Write and solve a quadratic equation. A right triangle has a hypotenuse of 105 inches. One leg is forty-two inches less than double the other leg. What is the length of the shorter leg? (Hint: a^2+b^2=c^2)
I just need help with this question. If you could show step by step that would be perfect thanks!
The "other" leg is the shorter leg, which we'll call, S
Then the longer leg = 2S - 42
Using pythag theorem, a%5E2+%2B+b%5E2+=+c%5E2, we get: highlight_green%28S%5E2+%2B+%282S+-+42%29%5E2+=+105%5E2%29
S%5E2+%2B+4S%5E2+-+168S+%2B+%221%2C764%22+=+%2211%2C025%22 ------ FOILing %282S+-+42%29%5E2
5S%5E2+-+168S+%2B+%221%2C764%22+-+%2211%2C025%22+=+0
matrix%281%2C2%2C+%22%2A%2A%22%2C+5S%5E2+-+168S+-+%229%2C261%22+=+0%29
5S%5E2+-+315S+%2B+147S+-+%229%2C261%22+=+0 ------ Replacing - 168S with - 315S + 147S
5S(S - 63) + 147(S - 63) = 0
(S - 63)(5S + 147) = 0
S - 63 = 0 OR 5S + 147 = 0
S, or length of the shorter leg = highlight_green%28matrix%281%2C2%2C+63%2C+inches%29%29 OR S+=+-+147%2F5 (ignore)
** You could also solve this quadratic equation by: using the quadratic equation formula, COMPLETING THE SQUARE, or GRAPHING. However, graphing is most-often not used.