How do you solve #4x-y=7# and #2x-3y=-9# using substitution?

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Answer 1 · 2018-04-30T07:05:29

By arranging the equations

First equation can be arranged as:

#4x-7 = y#

Put this y into the second equation (instead of y use #4x-7#):

#2x - 3(4x-7) = -9#

#2x - 12x + 21 = -9#

#-10x = -9-21#

#-10x = -30#

#x = 3#

y can be obtained using the first equation:

#y = 4x-7#

#y= (4times3) - 7#

#y= 12-7#

#y= 5#

Your solution #x=3# and #y=5#