Question

Use the quadratic formula to solve x² + 8x + 9 = 0. What are the solutions to the equation? Round irrational solutions to the nearest tenth.  

x=−1.2 and x=−6.8
x = 1 and x=−9
x=−6.6 and x=−1.4
x=−1 and x=−8

Answer 1

the answer is .C..........

Answer 2

The solution set is x=-6.6 and x=-1.4

Option 3 is correct.

Explanation:

Given:
`x^2+8x+9=0`

Formula:
`x=(-b\pm√(b^2-4ac))/(2a)`

For given equation,
`x^2+8x+9=0`

a=1 , b=8 and c=9

Substitute the value of a, b and c into quadratic formula.

`x=(-8\pm√(8^2-4\cdot 1\cdot 9))/(2(1))`

`x=(-8\pm√(64-36))/(2)`

`x=(-8\pm√(28))/(2)`

`x=(-8\pm2√(7))/(2)`

`x=-4\pm √(7)`

`x=-4-2.65\approx -6.6`

`x=-4+2.65\approx -1.4`

Hence, The solution set is x=-6.6 and x=-1.4