# Help with Division and Quadratic equation

• October 10th 2007, 01:46 PM
Kblack
Help with Division and Quadratic equation
1) Calculate the divisions
5 – 3i/2 + i

4i/2 -i

x2 + 2x + 3 = 0

X2 + 4x + 5 = 0
• October 10th 2007, 05:28 PM
ThePerfectHacker
Quote:

Originally Posted by Kblack
1) Calculate the divisions
5 – 3i/2 + i

4i/2 -i

x2 + 2x + 3 = 0

X2 + 4x + 5 = 0

Use the quadradic formula and post what you get so we can check.
• October 10th 2007, 05:39 PM
Jhevon
Quote:

Originally Posted by Kblack
1) Calculate the divisions
5 – 3i/2 + i

4i/2 -i

to divide by a complex number, we multiply by it's conjugate over itself, thus:

$\frac {5 - 3i}{2 + i} = \frac {5 - 3i}{2 + i} \cdot \frac {2 - i}{2 - i}$

and

$\frac {4i}{2 - i} = \frac {4i}{2 - i} \cdot \frac {2 + i}{2 + i}$

now simplify