If the lines $4x + 3y - 1 = 0$,$x - y + 5 = 0$,and $kx + 5y - 3 = 0$ are concurrent,then $k=$

If $4a^2 + 9b^2 - c^2 + 12ab = 0$, then the family of straight lines $ax + by + c = 0$ is concurrent at

Three lines $3x - y = 2$,$5x + ay = 3$,and $2x + y = 3$ are concurrent. Find the value of $a$.

If $k_{i}$ are possible values of $k$ for which lines $kx + 2y + 2 = 0$,$2x + ky + 3 = 0$,and $3x + 3y + k = 0$ are concurrent,then $\sum k_{i}$ has the value

The three straight lines $ax + by = c$,$bx + cy = a$ and $cx + ay = b$ are concurrent,if

The number of values of $a$ for which the system of equations $a^2 x + (2 - a) y = 4 + a^2$ and $a x + (2 a - 1) y = a^5 - 2$ possesses no solution is: