How do solve the following linear system?: x= y - 11 x, y = 4x + 4 ?

1 Answer
Alan P.
Jun 16, 2016

(x,y)=color(green)(""(1/2,6))

Explanation:

Given
[1]color(white)("XXX")x=y-11x
[2]color(white)("XXX")y=4x+4

There are several ways to solve this, but it seems to be set up for substitution;
so, substituting, from [2], 4x+4 for y in [1]
[3]color(white)("XXX")x=4x+4-11x

[4]color(white)("XXX")8x=4

[5]color(white)("XXX")x=1/2

then, substituting, 1/2 for x in [2]
[6]color(white)("XXX")y=4*(1/2)+4

[7]color(white)("XXX")y=6

(or course, as always, you should plug these values back into both original equations to verify your results)

Related questions
See all questions in Systems Using Substitution
Impact of this question
1168 views around the world
You can reuse this answer
Creative Commons License