How do you solve - x+y=6 and -2x+y=7 using matrices?

1 Answer
A08
Feb 9, 2016

x=-1, y=5

Explanation:

As the equations are already in the form Ax+By=C, writing all the coefficients of each equation to form each row of the matrix as below
M=[(-1,1,|,6),(-2,1,|,7)]
Now by row operations change 2xx2 matrix on the left side to identity matrix.

M=[(1,0,|,-1),(-2,1,|,7)]
Changed row 1 By subtracting row 2 from row 1

M=[(1,0,|,-1),(0,1,|,5)]
Changed row 2 By adding 2 xxrow 1 to row 2

From right column we obtain the solution as

x=-1, y=5

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