How do you solve 5x+4y = -1 and 2x+y = -4?

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Answer 1 · 2018-04-22T21:38:34

#x=-5# and #y=6#

Simultaneous linear equations:

#5x+4y=-1#
#2x+y=-4#

We want to cancel out either y or x so we only solve for one of them first.

Multiply the first equation by 2 and second equation by 5, so that the x's will cancel out:

#10x+8y=-2#
#10x+5y=-20#

Then subtract:

#3y = 18#
#y = 18/3#
#y=6#

Substitute #y# back into one of the original equations (I chose #5x+4y=-1#):

#5x + 4(6) = -1#
#5x + 24 = -1#
#5x = -1-24#
#5x = -25#
#x = -25/5#
#x= -5#

Hope this helped.