Solve for x. 5x - 3 = 12 x = 9/5 x = -9/5 x = 3 x = -3

5x - 3 = 12 5x = 12 + 3 5x = 15    [:5 x = 3      the right answer x = 3 Check 5 *x - 3 = 12 5 * 3 - 3 = 12 15 - 3 = 12 L = R

Hi there! We have to find out what the mystery number is (x). First, we add 3 to both sides, 5x-3+3=12+3 which equals 5x=15. Then, we divide both sides by 5, 5x/5=15/5, 15/5=3. Therefore, our mystery number is 3, so the answer is x=3.