How do solve the following linear system?: # x + y = 2, y = 4x + 4 #?

1 Answer
Jan 25, 2016

Answer:

You could use the "Substitution Method" to get
#color(white)("XXX")(x,y)=(-2/5,12/5)#

Explanation:

Given:
[1]#color(white)("XXX")x+y=2#
[2]#color(white)("XXX")y=4x+4#

Substitute #4x+4# for #y# (from equation [2]) in equation [1]
[3]#color(white)("XXX")x+4x+4=2#

Simplify equation [3]
[4]#color(white)("XXX")5x=-2#

[5]#color(white)("XXX")x=-2/5#

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

Simplify
[7]#color(white)("XXX")y=12/5#