linear equation

if(3,2) and (1,2) are solution of the equations ax+by=6 , find the values of a and b?

We have

a(3) + b(2)  =  6        and

a(1) + b(2)   = 6

Multiply the second equation by -1 and add it to the first....this gives

2a = 0        so...... a = 0

This means that 2b = 6   so b  = 3

And our equation  reduces to

3y = 6