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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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=8
Answer 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
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