# SOLUTION: Can someone explain how I am supposed to solve by substitution with the problems x-y=5 x+2y=7 and 3b+2a=2 -2b+2a=8

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 Click here to see ALL problems on Graphs Question 61341: Can someone explain how I am supposed to solve by substitution with the problems x-y=5 x+2y=7 and 3b+2a=2 -2b+2a=8Answer by jai_kos(139)   (Show Source): You can put this solution on YOUR website!pROBLEM 1 x-y=5 x+2y=7 sOLUTION: x-y = 5 ==> x = 5 + y Now substitute the value x = 5 + y in the second equation x + 2y =7 ==> 5 +y + 2y = 7 ==> 5 + 3 y = 7 ==> 3y = 7 -5 ==> y = 2/3 Now again we have x =5 + y ==> x = 5 + 2/3 ==> x = 17 /3 so the solution is x = 17/3 and y = 2/3 ---------------------------------------------------------------------------- 3b+2a=2 -2b+2a=8 ==> 2a = 8 + 2b ==> a = 8/2+ 2b/2 ==> a = 4 + b now substitute the value a = 4+b in the first equation, 3b + 2a = 8 ==> 3b+ 2 ( 4 + b ) = 8 ==> 3b+ 8 + 2b = 8 ==> 5b = 8-8 ==> 5b = 0 ==> b = 0/5 ==> b = 0 Now we have, a = 4 + b ==> a = 4 + 0 ==> a = 4. therefore solution is a = 4 and b = 0