# SOLUTION: How do you solve this three variable equation? d + e - f = 11 f + d + 5 = e 2e - 12 = f

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 Question 278160: How do you solve this three variable equation? d + e - f = 11 f + d + 5 = e 2e - 12 = fAnswer by ankor@dixie-net.com(15747)   (Show Source): You can put this solution on YOUR website!: How do you solve this three variable equation? d + e - f = 11 f + d + 5 = e 2e - 12 = f : Arrange all in the same order d + e - f = 11 d - e + f = -5 0 +2e - f = 12 : Multiply the 1st equation by - 1 -d - e + f = -11 d - e + f = -5 0 + 2e - f = 12 --------------------adding eliminates d and e, find f 0 + 0 + f = -4 f = -4 : Find e using the last equation 2e - f = 12 2e - (-4) = 12 2e + 4 = 12 2e = 12 - 4 2e = 8 e = +4 : Find d using the 1st equation d + e - f = 11 d + 4 (-4) = 11 d + 4 + 4 = 11 d = 11 - 8 d = 3 : Check solutions in the 2nd equation d - e + f = -5 3 - 4 - 4 = -5