# Need help with Elimination (Linear Equation)

• Sep 27th 2008, 11:12 AM
largebabies
Need help with Elimination (Linear Equation)
So, i'm having a very difficult time understanding elimination and would appreciate anyones help on that matter (most of my class feels the same, so i'm not alone in this, for once :P)

The equation that i'm stumped on is.

2x + 4y = 7
4x - 3y = 3

I understanding the graphing and subsitution methods pretty well but not this method.

A step-by-step walkthrough would help alot with this.

Any help?
• Sep 27th 2008, 11:16 AM
Jhevon
Quote:

Originally Posted by largebabies
So, i'm having a very difficult time understanding elimination and would appreciate anyones help on that matter (most of my class feels the same, so i'm not alone in this, for once :P)

The equation that i'm stumped on is.

2x - 4y = 7
4x - 3y = 3

I understanding the graphing and subsitution methods pretty well but not this method.

A step-by-step walkthrough would help alot with this.

Any help?

the point is, you want to eliminate one of the variables so that you can solve for the other. to do this, you must have the coefficients of the variable you want to eliminate to be equal to each other (except maybe by a factor of a minus sign). now, lets say we want to eliminate x. we want the coefficients of x in both equations to be equal, in which case we can subtract one equation from the other and get rid of the x. (if we make one coefficient the negative of the other, then we simply add both equations).

so lets do that. eliminate the x. what would you do to get the coefficients of x the same in both equations?
• Sep 27th 2008, 11:33 AM
largebabies
Opps, I made a mistake writing the equation out.

It's 2x + 4y = 7, not 2x - 4y = 7.

Does that change anything?
• Sep 27th 2008, 11:39 AM
Jhevon
Quote:

Originally Posted by largebabies
Opps, I made a mistake writing the equation out.

It's 2x + 4y = 7, not 2x - 4y = 7.

Does that change anything?

no

it will change the solution, but not the method, of course

so continue :)