quadratic equation roots

[Var1995]

the solution is (-infinity, 0) U (4, infinity). b is the right option. this is easy but just want to confirm. someone pls check

[Var1995]

how do i solve it?

[Obi Wan]

You seem to be right about question 18

For question 23, my answer is  > 0

[Var1995]

how did u arrive at your answer?

[Obi Wan]

[Var1995]

i m getting (-27+18a)/2a^2 after solving the expression and this will give us a negative no. implying option d as the correct one. pls check