How do you solve 4x-y=-9 and 2x+y=-3?

1 Answer
Jun 15, 2016

Answer:

#(x,y)=(-2,1)#

Explanation:

[1]#color(white)("XXX")4x-y=-9#
[2]#color(white)("XXX")underline(2x+y=-3)#
[3]#color(white)("XXX")6xcolor(white)("XxX")=-12color(white)("XXX")# after adding [1] and [2]

[4]#color(white)("XXX")x=-2color(white)("XXXXXXX")#after dividing both sides of [3] by #6#

[5]#color(white)("XXX")-8-y=-9color(white)("XXXX")#after substituting #(-2)# for #x# in [1]

[6]#color(white)("XXX")y=1color(white)("XXXXXXX")#after adding #8# to both sides of [5] then dividing by #(-1)#