Question

Which of the following equations has only one solution?

X( x - 1) = 9
x2 - 6x + 9 = 0
x2 = 9

Answer 1

x^2 - 6x + 9

Explanation:

x(x - 1) = 9

x^2 - x - 9 = 0

x = 3.54 or x = -2.54 (using quadratic formula)

x^2 - 6x + 9 = 0

(x-3)^2 = 0

x = 3

x^2 = 9

x = ±√3 (any positive number square rooted always have 2 answers)