How do you solve 2x - 5y = 11 and 4x + 10y = 18?

1 Answer
Sep 17, 2015

Answer:

#(x,y) = (5, -1/5)#

Explanation:

[1]#color(white)("XXX")2x-5y=11#
[2]#color(white)("XXX")4x+10y=18#

Multiply [1] by #2#
[3]#color(white)("XXX")4x-10y=22#

Subtract [3] from [2]
[4]#color(white)("XXX")20y = -4#

Divide [4] by #20#
[5]#color(white)("XXX")y = -1/5#

Substitute #(-1/5)# for #y# in [1]
[6]#color(white)("XXX")2x-5(-1/5)=11#

Simplify
[7]#color(white)("XXX")2x+1=11#

Subtract #1#
[8]#color(white)("XXX")2x=10#

Divide by #2#
[9]#color(white)("XXX")x=5#