anonymous 5 years ago how do you solve 2+4x+x square=0 and getting the answers -0.59, -3.41

1. amistre64

combine like terms: 2 +4x +x = 0.....x square?

2. amistre64

x^2 + 4x + 2 = 0 -2 +- sqrt(2)

3. anonymous

yes x square i dont know how to write the little two on the top

4. amistre64

the 6 button has a caret if your shift it :) x^2

5. anonymous

ok.. so how do i get the answers -0.59 and -3.41 by doing this equation???

6. anonymous

$x^2+4x+2=0$ is a quadratic equation ( a polynomial of second degree).. The discriminant is $Δ=4^2-4*1*2=8$ so the roots are $x_1=(-4+\sqrt{Δ})/(2*1)=-0.59$ and $x_2=(-4-\sqrt{Δ})/(2*1)=-3.41$ For more information try: http://en.wikipedia.org/wiki/Quadratic_equation

7. anonymous

I should add that when you have a quadratic equation $ax^2+bx+c=0$ the discriminant is $Δ=b^2-4ac$ and the roots are $x1=(-b+\sqrt{Δ})/2a$ and $x2=(-b-\sqrt{Δ})/2a$