
Will N. answered 05/24/15
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Expert Math Tutor
You're actually done with the first part of the problem -- the matrix is in row echelon form and you have done it correctly. The next step is to recognize that this matrix corresponds to the system
x+5y=-6
16y=16
To find y, use the second equation:
16y=16
y=1
Back substituting means substituting this value for y into the first equation and solving for x:
x+5(1)=-6
x=-11
So the solution is x=-11,y=1. I hope this helps.