Question

If the sides of a square are lengthened by 8cm, the area becomes 289cm^2. Find the length of a side of the original square.

I do not know how to do this please help me.

Answer 1

let the original side of the square be x cm, then the new square will have side (x+8) cm

new area = 289

(x+8)^2 = 289

x^2 + 16x + 64 = 289
x^2 + 16x - 225 = 0
(x+25)(x-9) = 0

etc.

Answer 2

thanks