Question

Solve the quadratic equation ×^ +8×+9=0 by
formula
method.​

Answer 1

Step-by-step explanation:

Quadratic formula = +- b^2 - 4ac

- - - - - - - - - - -

2a

Answer 2

Answer :

x = -4 ± √7

Solution :

Here ,

The given quadratic equation is ;

x² + 8x + 9 = 0

Now ,

Comparing the given quadratic equation with the general quadratic equation ax² + bx + c = 0 , we have ;

a = 1

b = 8

c = 9

Now ,

The discriminant of the given quadratic equation will be given as ;

=> D = b² - 4ac

=> D = 8² - 4•1•9

=> D = 64 - 36

=> D = 28

Now ,

The roots of the given quadratic equation will be given as ;

=> x = (-b ± √D)/2a

=> x = (-8 ± √28)/2•1

=> x = (-8 ± 2√7)/2

=> x = 2(-4 ± √7)/2

=> x = -4 ± √7

Hence , x = -4 ± √7