How to solve three linear equations in two variables?

see to solve the equation which only contains 2 variables noly 2 eqautions are needed.however if 2 equations are complex(difficulty in geeting value of variables)we can use 3^rd equation also.let me now consider 2 equation of standard forms

 

 

Ax+By+C=0

ax+by+c=0

 

now on solving for x in 1^st eqnt we get”x={-(C+By)}/A

and putting this value in 2^nd equation we get:y={aC-Ac}/Ab-Ba

hope u understand