The straight line that passes through the point of intersection of the straight lines $x + 2y - 10 = 0$ and $2x + y + 5 = 0$ is:

The three lines $lx + my + n = 0$,$mx + ny + l = 0$,and $nx + ly + m = 0$ are concurrent if:

The points $A(1, 2)$,$B(2, 4)$,and $C(4, 8)$ form a/an

If the points $(k, 2 - 2k)$,$(1 - k, 2k)$ and $(-k - 4, 6 - 2k)$ are collinear,then the possible values of $k$ are

Let $a, b$ and $c$ be distinct and none of them is equal to $1$. If the lines $x+ay+a=0$,$bx+y+b=0$ and $cx+cy+1=0$ are concurrent,then the value of $\frac{a}{a-1}+\frac{b}{b-1}+\frac{c}{c-1}$ is

If the lines $x+3y-5=0$,$5x+2y-12=0$,and $3x-ky-1=0$ do not form a triangle,then a value of $k$ is