Answer:
The solution set is x=-6.6 and x=-1.4
Option 3 is correct.
Step-by-step explanation:
Given: \(x^2+8x+9=0\)
Formula: \(x=\dfrac{-b\pm\sqrt{b^2-4ac}}{2a}\)
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.
\(x=\dfrac{-8\pm\sqrt{8^2-4\cdot 1\cdot 9}}{2(1)}\)
\(x=\dfrac{-8\pm\sqrt{64-36}}{2}\)
\(x=\dfrac{-8\pm\sqrt{28}}{2}\)
\(x=\dfrac{-8\pm2\sqrt{7}}{2}\)
\(x=-4\pm \sqrt{7}\)
\(x=-4-2.65\approx -6.6\)
\(x=-4+2.65\approx -1.4\)
Hence, The solution set is x=-6.6 and x=-1.4
