Roy exclaims that his quadratic with a discriminant of -9 has no real solutions. Roy then puts down his pencil and refuses to do any more work. Create an equation with a negative discriminant. Then explain to Roy, in calm and complete sentences, how to find the solutions, even though they are not real.

Question

amistre64 · Answer

im with Roy ... why bother :)

axel.caballero · Answer

Youre funny @amistre64 but seriously your a moderator now, k'mon. Can you  help ?

mathstudent55 · Answer

The discriminant is $b^2 - 4ac$.

Come up with an equation of the form $ax^2 + bx + c = 0$  for which  $b^2 - 4ac$   comes out negative.

amistre64 · Answer

if Roy knows about a discriminant, then they most likely know the quadratic formula as well.  Right?

amistre64 · Answer

..and i know math55 here is capable

mathstudent55 · Answer

Use a small number for b, and positive numbers for a and c, so that when you multiply 4ac you get a larger number than b^2.

mathstudent55 · Answer

@axel.caballero 
Are you following along?

axel.caballero · Answer

@mathstudent55 yes, its just i only get on here and hour a day. what are the steps in solving this ?

axel.caballero · Answer

@amistre64  you should totes help me, this guy went offline.

mathstudent55 · Answer

Let's come up with an example of a quadratic equation and check its discriminant.

Let's try  $ x^2 + 2x + 4$.

In this case, $ a = 1, ~b = 2, ~c = 4$.

The discriminant is
$b^2 - 4ac = 2^2 - 4 \cdot 1 \cdot 4= 4 - 16 = -12$

As you can see, the discriminant is negative, so there are no real solutions to this quadratic equation.

axel.caballero · Answer

Oh i see, this makes more sence. thanks! @mathstudent55