Question

How do you solve the linear equation x-y =12 and 2x+y=3 using the substitution method?

Answer 1

`(x,y)to(5,-7)`

Explanation:

`x-y=12to(1)`

`2x+y=3to(2)`

`"from equation "(2)toy=3-2xto(3)`

`color(blue)"substitute "y=3-2x" into equation "(1)`

`x-(3-2x)=12`

`x-3+2x=12`

`"add 3 to both sides"`

`3x=15`

`"divide both sides by 3"`

`x=15/3=5`

`"substitute "x=5" into equation "(3)`

`y=3-10=-7`

`"point of intersection "=(5,-7)`
graph{(y+2x-3)(y-x+12)((x-5)^2+(y+7)^2-0.04)=0 [-20, 20, -10, 10]}