How do you solve the system of equations: 3x+y=3 and x+2y=-4?

1 Answer
Aug 15, 2015

Answer:

The solutions are
#color(blue)(x=2,y=-3#

Explanation:

#color(blue)(3x)+y=3 #................equation #1#

# x+2y=-4#, multiplying this equation by #3#
# color(blue)(3x)+6y=-12#........equation #2#

Now, we can solve the equations by elimination as #color(blue)(3x)# is common to both equations.

Subtracting equation #2# from #1#
#cancelcolor(blue)(3x)+y=3 #
# -cancelcolor(blue)(3x)-6y=+12#

#-5y=15#
#color(blue)(y=-3#

Finding #x# by substituting #y# in equation #2#
# x+2y=-4#
# x=-4-2y#
# x=-4-2*-3#
# x=-4+6#
#color(blue)(x=2#