Question

Rationalize the denominator

Answer 1

in this question i is sqrt-1, so 7-2i-(4+9i) = 3+7i, and applying
(a+b)(a-b) = a^2 -b^2, and treating (3+7i) as (a+b), what do you have for (a-b)?

Answer 2

you still here?

Answer 3

yes im still here. sorry, i was trying to solve my next quiestion while I was waiting for you to complete typing. :P sorry

Answer 4

7-2 for (a-b)

Answer 5

isn't 7-2i-(4-9i) suppose to be 3-11i

Answer 6

sorry 7-2i-(4+9i)=3-11i

Answer 7

right sorry! :P, so, (a-b) =3-11i, and (a+b) = 3+11i

Answer 8

you eliminate the i in the denominator by multiplying (3+11i) to the denominator and the numerator.

Answer 9

i squared = sqrt-1 x sqrt-1= -1

Answer 10

ok i think im following

Answer 11

remember for sqrt(-49)=7i

Answer 12

alright

Answer 13

in the end you should have 7i(3+11i) for the numerator and (3-11i)(3+11i) for the denominator, can you continue from this?

Answer 14

is this right?

Answer 15

you got the numerator right, but not the denominator.

Answer 16

the denominator is (3-11i)(3+11i)

Answer 17

-77+21i/130??

Answer 18

yes!

Answer 19

aww why thanks! i see what I did wrong too :)

Answer 20

good, practice makes perfect!