$25(x+y{)}^2-4(x-y{)}^2$ is equal to

Q. The equation $25(x^2+y^2-2x+1)=(4x-3y+1{)}^2$ represents

Q.

The locus of a point which divides the join of A(-1, 1) and a variable point P on the circle $x^2+y^2=4$ in the ratio 3:2, is

Q. The equation of the circle passing through (1, 1) and the points of intersection of $x^2+y^2+13x-3y=0$ and $2x^2+2y^2+4x-7y-25=0$ is

Q. If the abscissas and ordinates of two points $P$ and $Q$ are the roots of the equations $x^2-7x+10=0$ and $x^2+7x+12=0$ respectively, then the equation of the circle with $PQ$ as diameter is