Question

Which of the following equations has the product of its roots as 4 ? 

A) x² + 4x – 4 = 0 

B) x² + 4x + 4 = 0 

C) x² + 4x – 24 = 0 

D) -x² + 4x + 4 = 0

Answer 1

Correct option is (B) x² + 4x + 4 = 0

If \(ax^2+bx+c=0\) is quadratic equation.

Then product of roots \(=\frac ca\)

(A) \(x^2+4x-4=0\)

\(\therefore\) Product of roots \(=\frac{-4}{1}=-4\)

(B) \(x^2+4x+4=0\)

\(\therefore\) Product of roots \(=\frac{4}{1}=4\)

(C) \(x^2+4x-24=0\)

\(\therefore\) Product of roots \(=\frac{-24}{1}=-24\)

(D) \(-x^2+4x+4=0\)

\(\therefore\) Product of roots \(=\frac{4}{-1}=-4\)

Answer 2

Correct option is B) x² + 4x + 4 = 0