eq.1 4x+3y=7eq.2 3x+7y=16
You want to eliminate one of the variables (either x or y) reducing the problem to just one equation with one variable which can be solved. This can be done by multiplying each equation by a factor and then subtracting one equation from the other. In this case, eliminating x.
Multiplying eq1. by 3 gives: eq.3 12x+9y=21eq.2 by 4 gives: eq.4 12x+28y=64Then subtracting eq.3 from eq.4 (to give a positive multiple of y, although the opposite calculation could be done) leaves: 19y=43 therefore y=43/19. Subbing this number back into either of the original equations solves for x. A check can be performed by subbing both obtained values into the other equation and ensuring the answer is consistent.