Question

State the value of the discriminant. Then determine the number of real roots of the equation.

n(7n + 8) = -10


a) –216, 0 real roots


b) 24, 2 real roots


c) –226, 2 real roots


d) –272, 0 real roots

Answer 1

D < 0 So, it would have 2 imaginary roots.

Explanation:

Given : n(7n + 8) = -10.

To find : State the value of the discriminant. Then determine the number of real roots of the equation.

Solution : We have given n(7n + 8) = -10.

On distributing n over (7n + 8).

7 n² + 8n = -10.

On adding 10 both side to make it in standard form ax² + bx + c = 0.

7 n² + 8n + 10 = 0.

Discriminant = b² - 4ac.

Here a = 7 , b= 8 , c = 10.

Discriminant = 8² - 4(7)(10).

D = 64 - 280.

D = - 216

H ere, D < 0 So, it would have 2 imaginary roots.

Therefore, D < 0 So, it would have 2 imaginary roots.