## Elementary Geometry for College Students (6th Edition)

A quadratic equation can be written in this form: $ax^2 + bx+c = 0$ where $a,b,$ and $c$ are real numbers and $a \neq 0$ If $b=0$ or $c= 0$ (or both), then it is an incomplete quadratic equation. (a) $x^2-4 = 0$ $a=1, b = 0, c=-4$ This is an incomplete quadratic equation. (b) $x-4x=0$ $-3x=0$ $a=0, b = -3, c=0$ This is not a quadratic equation since $a=0$. (c) $3x^2 = 2x$ $3x^2-2x=0$ $a=3, b = -2, c=0$ This is an incomplete quadratic equation. (d) $2x^2-4 = 2x^2+8x$ $8x+4=0$ $a=0, b = 8, c=4$ This is not a quadratic equation since $a=0$. (e) $x^2 = 4$ $x^2-4=0$ $a=1, b = 0, c=-4$ This is an incomplete quadratic equation. (f) $x^2-2x-3 = 0$ $a=1, b = -2, c=-3$ This is not an incomplete quadratic equation.