Question

Solve the following pair of linear equation

1) px+qy=p-q

qx-py=p+q

Answer 1

Px+qy=p-q ---------(1)
qx-py=p+q ---------(2)
Multiplying (1) with p and (2) with q we get,
p²x+pqy=p²-pq -----------(3)
q²x-pqy=pq+q² -----------(4)
Adding (3) with (4) we get,
p²x+q²x=p²+q²
or, x(p²+q²)=p²+q²
or, x=1
Putting in (1) we get,
p.1+qy=p-q
or, qy=p-q-p
or, qy=-q
or, y=-1
∴, x=1 and y=-1