Please help:
If the sides of a square are lingthened by 7cm, the area becomes 169cm^2. Fine thelength of a side of the orginal square.
If the original side is s,
(s+7)^2 = 169 = 13^2
s+7 = 13
s = 6
s = -20 also satisfies the original equation, but does not fit the real world.