Question

How do you solve by substitution `x=3-3y` and `4y=x+11`?

Answer 1

`(x,y)to(-3,2)`

Explanation:

`x=3-3yto(1)`

`4y=x+11to(2)`

`"since equation "(1)" gives x in terms of y we can "color(blue)"substitute ""it directly into equation "(2)`

`4y=3-3y+11`

`"add 3y to both sides"`

`4y+3y=3cancel(-3y)cancel(-3y)+11`

`rArr7y=14`

`"divide both sides by 7"`

`(cancel(7) y)/cancel(7)=14/7`

`rArry=2`

`"substitute "y=2" into equation "(1)`

`x=3-(3xx2)=-3`

`"solution is "x=-3" and "y=2`