The 2 equations are -2x + y = -17 ---1) 3x + y = 23 ---2) we need to have the same coefficient for one of the variables. Already y variable has the coefficient of 1 for both equations so we can use the equations as it is. 2) - 1) subtract 1) from 2) 3x-(-2x) + y -y = 23-(-17) 5x = 40 x = 8 substituting x = 8 in the 2nd equation 3*8 + y = 23 24 + y = 23 y = -1
