Contrapositive of the statement. 'If two numbers are equal, then their squares are equal' is

Let A and B be $3 \times 3$ real matrices such that A is symmetric matrix and B is skew-symmetric matrix. Then the system of linear equations $\left(A^2 B^2-B^2 A^2\right) X=O$. where $X$ is $3 \times 1$ column matrix of unknown variables and $O$ is a $3 \times 1$ null matrix, has

If $\mathrm{f}(x)=x^3-10 x^2+200 x-10$, then

The number of common tangents to the circles $x^2+y^2-x=0$ and $x^2+y^2+x=0$ is /are