Question

How do you solve `x + 4y = 12` and `2x - 3y = 6` using substitution?

Answer 1

`x=60/11andy=18/11`

Explanation:

Here,`x+4y=12...to(1)and2x-3y=6...to(2)`

From `(1) color(red)(x=12-4y)...to(3).`

substituting value of x in `equ^n(2)`,we get

`2color(red)((12-4y))-3y=6=>24-8y-3y=6`

`=>24-6=8y+3y=>18=11y=>y=18/11`

From(3),we have

`x=12-4(18/11)=(132-72)/11=60/11`

Check the answer:

from (1) `x+4y=12`

`=>LHS=60/11+4(18/11)=60/11+72/11=132/11=12=RHS`

graph{(x+4y-12)(2x-3y-6)=0 [-10, 10, -5, 5]}