How do you solve this set of linear system: #x- 2y = 7;y = - x + 1#?

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Answer 1 · 2016-11-26T14:22:10

#x = 3# and #y -2#

Because the second equation has already be solved for #y# you can substitute #-x + 1# for #y# in the first equation and solve for #x#:

#x - 2(-x + 1) = 7#

#x + 2x - 2 = 7#

#3x - 2 = 7#

#3x - 2 + 2 = 7 + 2#

#3x - 0 = 9#

#3x = 9#

#(3x)/3 = 9/3#

#x = 3#

We can now substitute #3# for #x# in the second equation and calculate #y#:

#y = -3 +1#

#y -2#