Two sides of a square are represented by xsquared + 8x and 5x + 28. What is the perimeter of the square?

Guest May 3, 2017

#2**+4 **

The sides of a square are the same length...so

x^{2} + 8x = 5x + 28 Subtract 5x from both sides.

x^{2} + 3x = 28 Subtract 28 from both sides.

x^{2} + 3x - 28 = 0 Factor.

(x + 7)(x - 4) = 0 Set each factor =0

x = -7 or x = 4

If x = -7, the side length = (-7)^{2} + 8(-7) = -7

But since this is the length of a side, we want a positive number, so x must = 4

If x = 4, the side length = 4^{2} + 8(4) = 48

perimeter = 4 * side length

perimeter = 4 * 48 = 192 units

hectictar
May 3, 2017