SOLUTION: Solve this problem by usonf the system.of substitution. x-4y=4 6x-3y= -18 Help!!

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Question 533995: Solve this problem by usonf the system.of substitution.
x-4y=4
6x-3y= -18
Help!!
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
(1) +x+-+4y+=+4+
(2) +6x+-+3y+=+-18+
Divide both sides by 3
(2) +2x+-+y+=+-6+
----------------
Solve (1) for x
(1) +x+=+4+%2B+4y+
Substitute this into (2)
(2) +2%2A%284+%2B+4y%29+-+y+=+-6+
(2) +8+%2B+8y+-+y+=+-6+
(2) +7y+=+-6+-+8+
(2) +7y+=+-14+
(2) +y+=+-2+
and, since
(2) +2x+-+y+=+-6+
(2) +2x+-+%28-2%29+=+-6+
(2) +2x+%2B+2+=+-6+
(2) +2x+=+-8+
(2) +x+=+-4+
The solution +x+=+-4+, +y+=+-2+
It's easy to verify this with a plot of the equations:
+graph%28+400%2C+400%2C+-10%2C+10%2C+-10%2C+10%2C+%281%2F4%29%2Ax+-+1%2C+2x+%2B+6+%29+