It will intersect X axis when Y = 0…ie. ax^2+bx+c = 0…has real roots… ie discriminant > 0 b^2 – 4ac >= o b^2 >= 4ac

Use (1): If a > 0, RHS depends on c.. Use (2): If c < 0, RHS depends on a… Combine both.. a>0 and c <0..so ac < 0 Since square of a number is always > 0…we can say that b^2 > 4ac.. Ans is C

iRat says

It will intersect X axis when Y = 0…ie. ax^2+bx+c = 0…has real roots…

ie discriminant > 0

b^2 – 4ac >= o

b^2 >= 4ac

Use (1):

If a > 0, RHS depends on c..

Use (2):

If c < 0, RHS depends on a…

Combine both..

a>0 and c <0..so ac < 0

Since square of a number is always > 0…we can say that b^2 > 4ac..

Ans is C