Q.

The straight lines x+2y-9=0, 3x+5y-5=0 and ax+by=1 are concurrent if the straight line 35x-22y+1=0 passes through

1 (a,b)  
2 (b,a)  
3 (a,-b)  
4 (-a,b)  

Ans.

(1)

For x+2y-9=0, 3x+5y-5=0, ax+by-1=0

to be concurrent |12-935-5ab-1|=0

⇒  35a-22b+1=0                    ...(i)

Comparing (i) with equation 35x-22y+1=0.

Hence line 35x-22y+1=0 should pass through (a,b).