Question 30478: how whould I solve the equations 6x-2y=10 and x-2y= negtive 5 by using the subtution method?
Answer by sdmmadam@yahoo.com(530)   (Show Source):
You can put this solution on YOUR website! solve the equations 6x-2y=10 and x-2y= negtive 5 by using the subtution method?
6x-2y =10 ----(1)
x-2y = - 5 ----(2)
Observe that(2) contains (1)x and hence it is easy find x in terms of y using(2)
From (2), we have
x = 2y-5 ----(*)
Putting (*) in (1), that is substituting for x in (1), we get
6(2y-5)-2y = 10
12y-30-2y = 10
(12y-2y)=10+30 (grouping like terms,changing sign while changing side)
10y = 40
y = 40/10 = 4
Putting y = 4 in (*), we have
x = 2y -5 = 2X4 - 5 = 8-5 = 3
Answer x = 3 and y= 4
Verification: Since we used (*)which is nothing but (2)for finding x using y,
we shall use (1)for verification.
x = 3 and y =4 in 6x-2y =10 ----(1)
LHS = 6x-2y = 6X3-2X4 = 18-8 = 10 = RHS
Therefore our values are correct
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