How do you solve 3x+4y=0 and x-4y= -8?

1 Answer
Mar 5, 2018

Answer:

#x=-2# and #y=3/2#

Explanation:

Given
[1]#color(white)("XXX")3x+4y=0#
[2]#color(white)("XXX")x-4y=-8#

Adding equations [1] and [2] together
[3]#color(white)("XXX")4x=-8#

Dividing both sides of [3] by #4#
[4]#color(white)("XXX")x=-2#

Substituting #(-2)# for #x# back in [2]
[5]#color(white)("XXX")(-2)-4y=-8#

#rarr#[6]#color(white)("XXX")-4y=-6#

#rar#r[7]#color(white)("XXX")y=3/2# ...or if you prefer a mixed number #y=1 1/2#