Find the smaller of the two roots of the equation
x²+8x+15=0.

Correct option is A

Given:

x²+8x+15=0

a = 1, b = 8 and c = 15

Formula Used: 

For any quadratic equation;

​$$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$ 

Where, $$\triangle = b^2 - 4ac$$ ​

Solution:

​$$\Delta = b^2 - 4ac = 8^2 - 4(1)(15) = 64 - 60 = 4$$​

​$$x = \frac{-8 \pm \sqrt{4}}{2(1)} = \frac{-8 \pm 2}{2}$$​

​$$x_1 = \frac{-8 + 2}{2} = \frac{-6}{2} = -3$$​

$$x_2 = \frac{-8 - 2}{2} = \frac{-10}{2} = -5$$ 

Thus, Smaller root is -5.