Chapter 9 - Quadratic Functions and Equations - 9-3 Solving Quadratic Equations - Practice and Problem-Solving Exercises - Page 552: 52

a) $x^2+1=0$ (no solution) b) $x^2-1=-1$ (one solution: $x=0$) c) $x^2-4 = 0$ (two solutions: $x=2, x=-2$)

a) $x^2+1=0$ $x^2+1-1=0-1$ $x^2 = -1$ (no solution) b) $x^2-1=-1$ $x^2-1+1=-1+1$ $x^2 = 0$ $\sqrt {x^2} =\sqrt 0$ $x = 0$ c) $x^2-4=0$ $x^2-4+4=0+4$ $x^2 = 4$ $\sqrt {x^2} =\sqrt 4$ $x = 2, x=-2$