Question

(2 + i) (4-3i)

Answer 1

First use the distributive property twice to expand

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

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

(2 + i) (4-3i) = 8 - 6i + 4i - 3i^2

and I'll let you finish up

Answer 2

keep in mind that i^2 = -1

Answer 3

So is the answer 10i-7?

Answer 4

- 6i + 4i is not 10i

Answer 5

the 6i is negative

Answer 6

-6i + 4i = ???

Answer 7

any ideas?

Answer 8

-2i

Answer 9

good

Answer 10

8 - 3i^2 = ???

Answer 11

9?

Answer 12

what was i^2 again?

Answer 13

keep in mind that

\[\Large i = \sqrt{-1}\]

by definition

Answer 14

-1

Answer 15

so squaring both sides gives you

\[\Large i^2 = -1\]

Answer 16

good

Answer 17

that means

8 - 3i^2 = 8 - 3(-1) = ???

Answer 18

so its -2i+11

Answer 19

or 11 - 2i

correct

Answer 20

Thank you!

Answer 21

you're welcome