How do you solve by substitution #x + 3y = 8# and #2x - y = 9#?

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Answer 1 · 2018-07-14T20:22:23

#x=5,y=1#

Solving the first equation for #x#:
#x=8-3y#
Substituting this ( for #x#)in the second equation

#2(8-3y)-y=9#

expanding

#16-6y-y=9#

#16-7y=9#
so

#7y=7# so #y=1#

and

#x=8-3#

#x=5#