SOLUTION: Solve the system by substitution x-4y=-19 -4x-5y=13

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Question 102598: Solve the system by substitution
x-4y=-19
-4x-5y=13
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!
I. x-4y=-19+ first find x in this one
II. -4x-5y=13
then we have
x+=+%284y%29+-+19 now put this in II. and find y
-%284%294y+– 19 – 5y+= 13
-16y+%2B+76+%96+5y+=+13
76+%96+13+=+21y
21y+=+63
y+=+63%2F21
y+=+3
Now we can calculate x
x+=+4y+%96+19
x+=+12+%96+19
x+=+-7
Check:
x+%96+4y+=+-+19
-7+%96+4%2A3+=+-19
-7+-12+=+-19
-19+=+-19
-4x-5y=13
-4%2A%28-7%29-5%2A3=13
28-+15=13
13+=13