How do you solve x+y=6 and x-y=2?

3 Answers
Mar 11, 2018

x=4x=4
y=2y=2

Explanation:

x+y=6|-yx+y=6y
x=6-yx=6y

color(red)(x)-y=2xy=2
color(red)(6-y)-y=26yy=2
6-2y=2|-662y=26
-2y=-4|:(-2)2y=4:(2)
y=2y=2

x+color(blue)(y)=6x+y=6
x+color(blue)(2)=6|-2x+2=62
x=4x=4

Mar 11, 2018

x = 4x=4

Explanation:

We can eliminate yy from the equation by adding the two together, as y + -y = y-y = 0y+y=yy=0
We must also add the other terms.
2x = 82x=8
x = 4x=4

Mar 11, 2018

x= 4, y= 2x=4,y=2

Explanation:

x+y=6x+y=6, and x-y=2xy=2
You can eliminate it or subtitute it.

A. Eliminate

x+y=6x+y=6
x-y=2xy=2
______ -
2y=4, y=22y=4,y=2
And it makes x=4x=4

B. Subtitute

x+y=6x+y=6
y=6-xy=6x

x-y=x-(6-x)=2xy=x(6x)=2

2x-6=22x6=2
2x=8, x=42x=8,x=4
x+y=4+y=6, y=2x+y=4+y=6,y=2