SOLUTION: the sides of the square are extended to form a rectangle. one side of the square is extended by 5 cm and the other side by 2 cm. the area of the rectangle is 130 cm². Find the leng

Algebra ->  Equations -> SOLUTION: the sides of the square are extended to form a rectangle. one side of the square is extended by 5 cm and the other side by 2 cm. the area of the rectangle is 130 cm². Find the leng      Log On


   

Question 888283: the sides of the square are extended to form a rectangle. one side of the square is extended by 5 cm and the other side by 2 cm. the area of the rectangle is 130 cm². Find the length at the side of the square.
Answer by rothauserc(4718) About Me  (Show Source):
You can put this solution on YOUR website!
let x be the length of a side of the square, then
130 = (x+5) * (x+2)
130 = x^2 +7x +10
x^2 +7x -120 = 0
factor the polynomial
(x+15)*(x-8) = 0
x = -15 or x = 8
we want the positive value for x
therefore, the length of a side of the square is 8 cm