Let x be the number. "twelve decreased by twice a number" ---> 12 - 2x "8 times the sum of number and 4" ---> 8(x + 4) 12 - 2x = 8(x + 4) 12 - 2x = 8x + 32 (distributive property) 12 = 10x + 32 (add 2x to both sides) -20 = 10x (subtract 32 from both sides) x = -2 (divide both sides by 10)