SOLUTION: The sum of number and twice its square is 35. Find the number.

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Question 1083315: The sum of number and twice its square is 35. Find the number.
Found 2 solutions by josgarithmetic, MathLover1:
Answer by josgarithmetic(39616) About Me  (Show Source):
You can put this solution on YOUR website!
This is the description: x%2B2x%5E2=35
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2x%5E2%2Bx-35=0

x=%28-1%2B-+sqrt%28281%29%29%2F4

Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!

let's a number be x
twice its square is 2x%5E2
i the sum of number and twice its square is 35, we have
2x%5E2%2Bx=35
2x%5E2%2Bx-35=0......use quadratic formula
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
x+=+%28-1+%2B-+sqrt%28+1%5E2-4%2A2%2A%28-35%29+%29%29%2F%282%2A2%29+
x+=+%28-1+%2B-+sqrt%28+1%2B280+%29%29%2F4+
x+=+%28-1+%2B-+sqrt%28+281+%29%29%2F4+
x+=+%28-1+%2B-+16.76%29%2F4+
solutions:
x+=+%28-1+%2B+16.76%29%2F4+
x+=++15.76%2F4+
x+=++3.94
or
x+=+%28-1+-+16.76%29%2F4+
x+=+-17.76%2F4+
x+=++-4.44

+graph%28+600%2C+600%2C+-10%2C+10%2C+-40%2C+10%2C+2x%5E2%2Bx-35%29+