Question

Solve using formula.

x² + 6x + 5 = 0

Answer 1

x² + 6x + 5 = 0
On comparing with the equation  

\[a x^2 + bx + c = 0\] 

a = 1, b = 6 and c = 5
Now 

= b² - 4ac

= 6² - 4 × 1 × 5

= 36 - 20

= 16

\[x = \frac{- b \pm \sqrt{b^2 - 4ac}}{2a}\] 

\[x = \frac{- 6 \pm \sqrt{16}}{2 \times 1} = \frac{- 6 \pm 4}{2}\]

\[ \Rightarrow x = \frac{- 6 + 4}{2} \text{ or } x = \frac{- 6 - 4}{2}\]

x = `(-2)/2`  or  x = `(-10)/2`

\[ \Rightarrow x = - 1 \text{ or } x = - 5\]

∴ -1 and -5 are roots of the given quadratic equation.