Q.

Let (α,β) be the centroid of the triangle formed by the lines 15x-y=82,6x-5y=-4 and 9x+4y=17. Then α+2β and 2α-β are the roots of the equation   [2023]

1 x2-7x+12=0  
2 x2-10x+25=0  
3 x2-14x+48=0  
4 x2-13x+42=0  

Ans.

(4)

Given lines are

15x-y=82  (i)

6x-5y=-4  (ii)

9x+4y=17  (iii)

After solving the equations, we get the co-ordinates as (6,8),(1,2) and (5,-7)

So, centroid, (α,β)=(6+1+53,8+2-73)=(4,1)

  α+2β=4+2=6;  2α-β=7

So, required equation is x2-13x+42=0