# GRE Quantitative Practice, Standard Multiple-Choice

*Question 1*

If *x*^{2} + 6*x* = –9, how many values of *x* are possible?

- none
- one
- two
- three
- infinitely many

## Explanatory Answer

First, restate the equation in standard quadratic form:

The trinomial on the left side of the equation is factorable into two identical binomials:x^{2}+ 6x+ 9 = 0

(x+ 3)(x+ 3) = 0

To find the roots, set each binomial factor equal to zero. Since the two factors are the same, the equation has only one root: –3. The correct response is (B).