How do you solve this system of equations: #3x + y = 5 and - x - y = 1#?

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Answer 1 · 2017-11-08T17:14:24

#x=3, y=-4#

#3x+y=5# ---- 1
#-x-y=1# ---- 2

from equation 2,

#x=-1-y#

substitute #x=-1-y# into equation 1

#3(-1-y)+y=5#
#-3-3y+y=5#
#-2y=8#
#y=-4#

substitute #y=-4# into #x=-1-y#

#x=-1-(-4)#
#x=3#