SOLUTION: A square's side is increased by 4 yards, which corresponds to an increase in the area by 80 square yards. How many yards is the side of the initial square?

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Question 639417: A square's side is increased by 4 yards, which corresponds to an increase in the area by 80 square yards. How many yards is the side of the initial square?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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A square's side is increased by 4 yards, which corresponds to an increase
in the area by 80 square yards.
How many yards is the side of the initial square?
:
Let x = the side of the initial square
then
x^2 = the initial area of the square
and
(x+4)^2 = the area of the new square
:
New area - initial area = 80 sq/yds
(x+4)^2 - x^2 = 80
FOIL(x+4)(x+4)
x^2 + 8x + 16 - x^2 = 80
x^2 - x^2 + 8x = 80 - 16
8x = 64
x = sqrt%2864%29
x = 8 yds the side of the initial square
:
:
Check this; new square side; 4 + 8:
12^2 - 8^2 =
144 - 64 = 80