If the straight lines `x+y-2-0,2x-y+1=0` and `a x+b y-c=0` are concurrent, then the family of lines `2a x+3b y+c=0(a , b , c)` are nonzero) is concurrent at (a) `(2,3)` (b) `(1/2,1/3)` (c) `(-1/6,-5/9)` (d) `(2/3,-7/5)`

Explanation

`|{:(1,1,-2),(2,-1,1),(a,b,-c):}| = 0`
or a+5b-3c=0
or `-(a)/(3)-(5)/(3)b+c = 0`
Hence, 2ax+3by+c=0 is concurrent at 2x = -1/3 and 3y=-5/3.
So, x=-1/6, y=-5/9.