# Math Help - quadratic equation problem

Hi I cant seem to find the roots of this x^2 - 5x + 12
I cant do it the -b formula or standard factors?

2. Originally Posted by wolfhound
Hi I cant seem to find the roots of this x^2 - 5x + 12
I cant do it the -b formula or standard factors?

The roots of this quadratic are complex numbers since its discriminant is negative: are you working with complex numbers or only with real ones? In the latter case your answer should be "there are no real roots to the equation"

Tonio

3. Originally Posted by wolfhound
Hi I cant seem to find the roots of this x^2 - 5x + 12
I cant do it the -b formula or standard factors?
well the discriminant is negative which means there are at most 2 complex roots to your equation.

4. Originally Posted by wolfhound
Hi I cant seem to find the roots of this x^2 - 5x + 12
I cant do it the -b formula or standard factors?
The discriminant is negative an so you will get two complex solutions. To find these use the quadratic formula

$x = \frac{5 \pm \sqrt{5^2-4\cdot 1 \cdot 12}}{2} = \frac{5 \pm i \, \sqrt{23}}{2}$

$x = \frac{5}{2} + i\, \frac{\sqrt{23}}{2} \: \text{or} \: \frac{5}{2} - i\, \frac{\sqrt{23}}{2}$

5. I was not working with complex numbers but thanks for showing me the other way

6. what does the i mean?
should it be square root of - 23?

7. Originally Posted by wolfhound
what does the i mean?
should it be square root of - 23?
$i = \sqrt{-1}$