The equation of the line perpendicular to the line ax+by−1=0 and passes through origin is, bx−ay=0 .....(I) Now, altitude passes through the intersection of the line 2x+3y−1=0 and x+2y−1=0 So, −b−a=0 a+b=0 ....(II) From above the line ax+by−1=0 becomes, x−y−
1
a
=0 ....(III) Now, the altitude perpendicular to the line 2x+3y−1=0 and passes through origin is, 3x=2y The point of intersection line (III) and x+2y−1=0 is, (
1
3
(1+
2
a
),
1
3
(1−
1
a
)) satisfy the line, a=−8andb=8 Thus, (a,b)=(−8,8)