We have two numbers that add to 42.... Call the larger number X and the smaller number Y X+Y = 42 We are told that Y is 12 less than X so Y = X-12 Substitute X-12 in place of Y in the original equation giving X + X -12 = 422X - 12 = 42Add 12 to both sides2X = 54Divide both sides by 2X = 27 Y = X-12 = 27 - 12 = 15 Our two numbers are 27, 15