Question

2x+y=1
9x + 3y = -3
The x-coordinate of the point of intersection is

Answer 1

how do you get rid of the y

Answer 2

There are two ways to get x. The so-called substitution method: Solve the first equation for y to get y=1-2x, then sub 1-2x into the x in the second equation:

9(1-2x)+3y=-3

Then solve for y, and back sub to get x

Answer 3

You can multiply the first equation throughout by 3, then subtract the first from the second.

Answer 4

I would rather multiply the first equation by -3 to get -6x-3y=-3 and add it to the second equation which will eliminate the y:

-6x+9x-3y+3y=-3-3 or 3x=-6 or x=-2

Answer 5

This is called the linear combination method or the elimination method