SOLUTION: the length of a square is increased by 2. Three times the area of the new square is 75. Find the length of the original square. I got 22 but I'm pretty sure that's wrong

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Question 858920: the length of a square is increased by 2. Three times the area of the new square is 75. Find the length of the original square. I got 22 but I'm pretty sure that's wrong
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Original square is side length x. area is x^2

New square, length increased to x+2, and implied is that this is also for a square, the area being %28x%2B2%29%5E2=x%5E2%2B4x%2B4. Described further is that 3%28x%5E2%2B4x%2B4%29=75
x%5E2%2B4x%2B4=75%2F3
x%5E2%2B4x%2B4=25
highlight_green%28x%5E2%2B4x-21=0%29.

Factoring that equation,
%28x-3%29%28x%2B7%29=0
One answer makes sense and one answer makes no sense. Take the positive solution for x.
highlight%28highlight%28x=3%29%29. Length of the original square was 3 units.