If $x^2 + y^2 = 25$ and $xy = 12$, then what is the value of $x^4 + y^4$?
If the equation of a straight line passing through the point (1,2) and perpendicular to the line $3x + 4y = 7$ is:
If $\tan A + \tan B = m$ and $\tan A \tan B = n$, then $\tan(A + B)$ is:
The value of the determinant \[ \begin{vmatrix} 2 & 3 & 5 \\ 1 & 0 & 4 \\ 7 & 2 & 1 \end{vmatrix} \] is: