MHT CET202122 Sep 2021Morning ShiftMathematicsPair of LinesActual
If slope of one of the lines a x^2+2 h x y+b y^2=0 is twice that of the other, then h ^2: ab is
Options
- A8 : 7
- B7 : 8
- C9 : 8
- D8 : 9
Correct answer
C. 9 : 8
Step-by-step solution
a x^2+2 h x y+b y^2=0 We have m ₁+ m ₂= -2 ~h ~b and m ₁ ~m ₂= a b aligned & Also m ₁+2 ~m ₂ & 3 ~m ₂=- 2 ~h ~b m ₂= -2 ~h 3 ~b and 2 ~m ₂^2= a b & 2 ( -2 ~h 3 ~b )^2= a b 8 ~h ^2 9 ~b ^2 = a b h ^2 ab = 9 8 aligned