Solve –2x2 – 16x – 44 = 0

(Choices below)

Question

Solve –2x2 – 16x – 44 = 0

(Choices below)

anonymous · Answer

attachment

anonymous · Answer

hey matt could you please help me in http://openstudy.com/#/updates/4eeed4c4e4b0367162f6046a after you are done here?

anonymous · Answer

What do you get when you use the quadratic equation?

matt101 · Answer

First divide the entire equation by -2:
$$x^2 +8x+22=0$$Then use the quadratic formula to find the solutions for x:
$$x=(-8\pm \sqrt{8^2-4(22)})/2$$$$=(-8\pm \sqrt{-24})/2$$$$=-4\pm i \sqrt{6}$$

anonymous · Answer

Why divide by -2?

anonymous · Answer

It's not necessary, just use a=-2

matt101 · Answer

You're right, you don't have to divide by -2. It just makes the numbers easier to work with when they're smaller.

anonymous · Answer

So that's not the correct answer?

matt101 · Answer

No it is. The original equation and the equation you get after dividing by -2 are equivalent. Using the quadratic formula on either will give you the same answer after you simplify the expression fully.

anonymous · Answer

Oh got it thank you

anonymous · Answer

Do you know how to use the quadratic formula?

anonymous · Answer

No we just learned it so I'm trying to get the hang of it

matt101 · Answer

So you probably have the quadratic formula equation in front of you. Where it says a, b, and c in the equation, you sub in the coefficients of x^2, x, and the constant respectively.

The answer you get are the solutions for x when y = 0 (i.e. the x-intercepts).