Thread: Complex Equation Help!

So, I'm having trouble with these complex equations. Any help would be great!

(2+3i)(3-4i)

2+i/3i

1+2i/1-i

Thanks again.

Lets try something like your problems

(3+4i)(1+2i)
= 3*1 + 4i*1 + 3*2i + 4i*2i
= 3 + 4i + 6i + 8i^2
= 3 - 8 + 10i
= -5 + 10i.

See how it's done?

(3+4i) / ( 2+i )
= (3+4i)(2-i) / (2+i)(2-i) multiply by 1, where 1 = (2-i)/(2-i).
= multiply out the top / multiply out the bottom.

Remember that and if you multiply a complex number by its conjugate you will get a real number.

e.g. the conjugate of is