Question

Elimination method
4x-2y=48
2x+6y=-18

Answer 1

4x - 2y = 48 ⇒ 4x - 2y = 48
2x + 6y = -18 ⇒ 4x + 12y = -36
-14y = 84
-14 -14
y = -6
4x - 2(-6) = 48
4x + 12 = 48
- 12 - 12
4x = 36
4 4
x = 9
(x, y) = (9, -6)

Answer 2

`4x-2y=48\\ \\ 2x+6y=-18`

First we'll multiply the second equation by -2



`-2\cdot (2x+6y)=-2\cdot -18\\ \\ -4x-12y=36`

Now let's add the new equation and the first one.


`(4x-2y)+(-4x-12y)=48+36\\ \\ 4x-4x-2y-12y=48+36\\ \\ -14y=84\\ \\ y=\frac { 84 }{ -14 } \\ \\ y=-6`

We found y's value. We'll plug it in one of the equations to find x's value.


`y=-6\\ \\ 4x-2y=48\\ \\ 4x-2\cdot -6=48\\ \\ 4x+12=48\\ \\ 4x=48-12\\ \\ 4x=36\\ \\ x=\frac { 36 }{ 4 } \\ \\ x=9`

Solution ;

(9, -6)