SOLUTION: The square of a positive number increased by 4 times the number is equal to 140. Find the number.

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Question 1009238: The square of a positive number increased by 4 times the number is equal to 140. Find the number.
Found 2 solutions by fractalier, MathLover1:
Answer by fractalier(6550) About Me  (Show Source):
You can put this solution on YOUR website!
Call the number, x. Then we have
x^2 + 4x = 140
x^2 + 4x - 140 = 0
(x + 14)(x - 10) = 0
x = -14 or x = 10
Thus
x = 10

Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!
let a positive number be x
if the square of a positive number increased by 4 times the number is equal to 140, we have
x%5E2%2B4x=140
x%5E2%2B4x-140=0
x%5E2%2B4x-140=0
x%5E2%2B14x-10x-140=0
%28x%5E2%2B14x%29-%2810x%2B140%29=0
x%28x%2B14%29-10%28x%2B14%29=0
%28x-10%29%28x%2B14%29+=+0
solutions:
if %28x-10%29+=+0=>x=10
if %28x%2B14%29+=+0=>x=-14
so, the number could be 10 or -14
but, since given condition is that we need "a positive number", your solution is number highlight%2810%29