If x² = 49, what are the possible values of x?

If x² = 49, then x = ±7 (both 7 AND −7), because 7² = 49 AND (−7)² = 49. ASVAB Mathematics Knowledge tests square roots and equations. KEY CONCEPT: when solving x² = a number, there are usually TWO solutions — a positive and a negative root — because squaring a negative number gives a positive result. COMMON ERROR: giving only the positive root (7). The square root symbol √ alone denotes the positive root, but solving the EQUATION x² = 49 yields both +7 and −7. Check: (−7)² = (−7)(−7) = 49. ✓