SOLUTION: If twice a number is added to it's square.the result is 143.find the number

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Question 1091926: If twice a number is added to it's square.the result is 143.find the number
Answer by ikleyn(52890) About Me  (Show Source):
You can put this solution on YOUR website!
.
2x+%2B+x%5E2 = 143.


x%5E2+%2B+2x = 143,

x%5E2+%2B+2x+%2B+1 = 143 + 1,

%28x%2B1%29%5E2 = 144  ====>

x + 1 = +/- sqrt%28144%29 = +/- 12.

x = -1 + 12 = 11  and  x = -1 - 12 = -13.

Answer.  There are  2  solutions:  11  and  -13.

Solved.