Question

Determine the number of real solutions of x^2 + 5x + 8 = 0.
A. 0
B. 1 (double root)
C. 2

Answer 1

DO i do the same ? This time it says of real solutions @Directrix

Answer 2

Do the same. Calculate the discriminant and post what you get.

By the way, a rational number is a kind of Real number. So, no worries on that when you look on the chart.

Answer 3

i get -7 thats irrational right

Answer 4

@Directrix

Answer 5

That is rational Reaper.

Answer 6

Let me help, just give me a moment to type.

Answer 7

Reaper534 This is a two step process. Get the discriminant first and then check the root chart.

Answer 8

-7 is the discriminant. You are correct.

Answer 9

@Reaper534 The roots will not be real. I wish you would consult the chart or actually crank out the roots. Whatever.

Answer 10

I am looking at chart

Answer 11

Descartes Rule Of Signs And the Theorem of Algebra will help us with this. The degree is 2 which means there are a total of 2 solutions(root/zeros). Count the number of times the sign changes. 0 times, so there are 0 positive real solutions. Now find f(-x) and count the number of sign changes. There are 2. So, there are 2 or 0 negative real solutions.. You have to test the possible solutions to determine if there are any negative solutions. There are no negative real roots, so there must be 2 complex/irrational roots.

Roots are solutions.

Answer 12

Thanks

Answer 13

@Reaper534 I hear you on wanting to learn how to do this. See how @DrJerry explains it here at the attachment. Okay?