Question

{(x,y) : x-3y=4}

x-3y=4
2x-6y=Q

Solve for Q? Are you supposed to use elimination? Is that possible without Q?

Answer 1

if we use elimination, we should make x or y the same size before subtracting

Answer 2

When I do that, -2(-2x+6y=-8) so -2x+6y=-8
2x-6y=Q
Both variables cross out, right?

Answer 3

exactly; so we get something like 0=-8+Q

Answer 4

How?

Answer 5

add the two lines:

-2x+6y=-8
2x-6y=Q
-------------
-2x+2x +6y-6y = -8+Q
0x + 0 y = -8+Q