Question

The zeroes of the polynomial x² - √2x – 12 are 

(a) √2, -√2 

(b) 3√2, -2√2 

(c) -3√2, 2√2 

(d) 3√2, 2√2

Answer 1

(b) 3√2, –2√2 

Let f(x) = x² – √2x – 12 = 0 

⇒ x² – 3√2x +2√2x – 12 = 0 

⇒ x(x – 3√2) + 2√2(x – 3√2) = 0 

⇒ (x – 3√2) (x + 2√2) = 0 

⇒ x = 3√2 or x = –2√2