How do you solve the system of equations #x- 4y = 12# and #5x + 4y = - 12#?

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Answer 1 · 2016-12-03T00:22:53

The solution is #(0,-3)#

#color(white)ax-4y=color(white)(aa)12#
#5x+4y=-12#

Add the equations together vertically.

#color(white)ax-4y=color(white)(aa)12#
#ul(5x+4y=-12)#
#6x+0color(white)(a)=color(white)(aa)0#

#6x=0#

#(6x)/6=0/6color(white)(aaa)#Divide both sides by 6

#x=0#

Substitute #color(red)x=color(red)0# into the first equation.

#color(red)0-4y=12#

#-4y=12#

#(-4y)/-4=12/-4color(white)(aaa)#Divide both sides by -4

#y=-3#

The solution is #(0,-3)#