Question

The square of a number exceeds the number by 72. Find the number

Answer 1

x^2 = x + 72

x^2 - (x+72) = 0

x^2 -x -72 = 0

x^2 - 9x + 8x -72 = 0

x(x-9)+8(x-9)=0

(x+8)(x-9)=0

x=9,x=-8