SOLUTION: Each side of a square is 4 meters long. When each side is increased by x meters, the area os doubled. Find the value of x.

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Question 343887: Each side of a square is 4 meters long. When each side is increased by x meters, the area os doubled. Find the value of x.
Answer by Fombitz(32388) About Me  (Show Source):
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Each side of a square is 4 meters long. When each side is increased by x meters, the area os doubled. Find the value of x.
The area of a square is,
A=s%5E2
Initially,
A%5B1%5D=4%5E2
A%5B1%5D=16
.
.
.
A%5B2%5D=%284%2Bx%29%5E2=32
16%2B8x%2Bx%5E2=32
x%5E2%2B8x-16=0
Use the quadratic formula,
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
x+=+%28-8+%2B-+sqrt%28+8%5E2-4%2A1%2A%28-16%29+%29%29%2F%282%2A1%29+
x+=+%28-8+%2B-+sqrt%28+64%2B64+%29%29%2F2+
x+=+%28-8+%2B-+8sqrt%28+2+%29%29%2F2+
x+=+-4+%2B-+4sqrt%282%29+
Only the positive answer makes sense in this situation.
x+=+-4+%2B+4sqrt%28+2+%29+
highlight%28x+=+4%28+sqrt%28+2+%29-1%29%29+