How do you solve the system x + y = 14 and -x + y = 16?

1 Answer
Alan P.
Jul 19, 2016

color(green)((x,y)=(-1,15))

Explanation:

Given
[1]color(white)("XXX")x+y=14
[2]color(white)("XXX")-x+y=16

Adding [1] and [2] gives
[3]color(white)("XXX")2y=30color(white)("XX")rarrcolor(white)("XX")y=15

Subtracting [2] from [1] gives
[4]color(white)("XXX")2x=-2color(white)("XX")rarrcolor(white)("XX")x=-1

Related questions
See all questions in Systems Using Substitution
Impact of this question
1038 views around the world
You can reuse this answer
Creative Commons License