SOLUTION: solve the following system of equations by substitution... please {{{-x+3y=11}}} {{{4x-y=-11}}}

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Question 159177: solve the following system of equations by substitution... please

-x%2B3y=11
4x-y=-11
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
-x%2B3y=11 equation 1
4x-y=-11 equation 2
.
Solve equation 1 for x:
-x%2B3y=11
3y=x%2B11
3y-11=x
.
Substitute the above into equation 2 and solve for y:
4x-y=-11
4%283y-11%29-y=-11
12y-44-y=-11
11y=33
y=3
.
Finally, substitute the above back into equation 1 and solve for x:
-x%2B3y=11
-x%2B3%283%29=11
-x%2B9=11
9=x%2B11
-2=x
.
Solution: x = -2 and y = 3