Question

How do you solve `x + y = 12` and `y = 2x` using substitution?

Answer 1

`(x,y)=(4,8)`

Explanation:

`color(blue)(x+y=12`

`color(blue)(y=2x`

Substitute the value given for `y` in the second equation to the first equation

`rarrx+2x=12`

`rarr3x=12`

`color(green)(rArrx=12/3=4`

Substitute the value of `x` to the second equation

`rarry=2(4)`

`color(green)(rArry=8`

`color(indigo)( :.ul bar |x,y=4,8|`