Question

Find the nature of roots of 4x^3-21x^2+18x+20=0

Answer 1

Answer:

Step-by-step explanation:

Let f(x) = 4x3 – 21x2 + 18x + 20

Then f'(x) = 12x2 – 42x + 18

= 6(2x2 – 7x + 3)

= 6(2x – 1)(x – 3)

Thus, f'(x) = 0 has 2 real roots

So, f(x) = 0 has 3 real roots.