Thread: I'm so lost! Please help.

Okay the paper says multiply by the conjuate

2+i
____ I think I multiply top and bottom by 4+2i but I'm not sure if I do that
4 +2i or if Im suppose to change the middle sign first or what..? Any advice?

Originally Posted by KeiaBlake

Okay the paper says multiply by the conjuate

2+i
____ I think I multiply top and bottom by 4+2i but I'm not sure if I do that
4 +2i or if Im suppose to change the middle sign first or what..? Any advice?

You multiply top and bottom by the complex conjugate of the denominator: 4 - 2i.

Originally Posted by KeiaBlake

Okay the paper says multiply by the conjuate

2+i
____ I think I multiply top and bottom by 4+2i but I'm not sure if I do that
4 +2i or if Im suppose to change the middle sign first or what..? Any advice?

The conjugate of 4+2i is 4-2i.

$\displaystyle \dfrac{2+i}{4+2i}=\dfrac{(2+i)(4-2i)}{(4+2i)(4-2i)} = \dfrac{8-4i+4i-(-2)}{16-(-4)}=\dfrac{10}{20}=\dfrac12$