How do you solve #x+3y=1# and #-3x-3y=-15# using substitution?
1 Answer
Apr 23, 2016
#x=7#
#y=-2#
Explanation:
Given_
#x+3y=1# ---------------- (1)
#-3x-3y=-15# -------------(2)
Solve Equation (1) for
#x=1-3y#
Substitute#x=1-3y# in equation (2)
#-3(1-3y)-3y=-15#
#-3+9y-3y=-15#
#-3+6y=-15#
#6y=-15+3=-12#
#y=(-12)/6=-2#
#y=-2#
Substitute
#x+3(-2)=1#
#x-6=1#
#x=1+6=7#
#x=7#
