Question

Find the zeroes of the quadratic polynomial 5x² -4 – 8x and verify the relation between the zeroes and its coefficients.

Answer 1

Given polynomial is 5x² – 4 – 8x 

= 5x² – 8x – 4 

= 5x² – 10x + 2x – 4 

= 5x(x – 2) + 2(x – 2)

= (x – 2) (5x + 2) 

To find zeroes, (x – 2) (5x + 2) = 0 

⇒ x – 2 = 0 or 5x + 2 = 0 

⇒ x = 2 or x = \(-\frac{2}{5}\)