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?