First of all, we can solve this by elimination (adding the 2 equations and eliminating 1 variable). 3x+10y=-47 5x+7y=40 It looks like we can eliminate the x by making one 15x, and the other -15x (15 is the least common multiple [LCM] of 3 and 5). 5 (3x+10y=-47) --> 15x+50y=-235 -3 (5x+7y=40) --> -15x-21y=-120 15x-15x = 0, 50y-21y = 29y, -235-120 = -355 0 + 29y = -355 29y/29 = -355/29 y = 12.24 then plugged that into 3x+10y=-47 3x+122.4=-47 3x+122.4-122.4=-47-122.4 3x = -169.4 x = 56.47 Something is wrong... are you sure the 2nd equation wasn't equal to NEGATIVE 40?? Or the 1st one equal to POSITIVE 40??
