Question

Simplify the expression. (–3i)( –4i)

Answer 1

@UnkleRhaukus

Answer 2

\[(-3i)(-4i)\\=(-1\times3\times i)\times(-1\times4\times i)\]we can rearrange
\[=(-1\times-1)\times(3\times4)\times(i\times i)\\=\]

Answer 3

1 x 12 x i^2?

Answer 4

12i^2?

Answer 5

\[=1\times12\times i^2\\=12i^2\]good.

Do you know what \(i^2 =?\)

Answer 6

no?

Answer 7

\[\boxed{i = \sqrt{-1}}\qquad\implies\qquad i^2=\sqrt{-1}\times\sqrt{-1}=-1\]

Answer 8

so i^2=-1

Answer 9

yeah, which makes
\[=12i^2\\=12(-1)\\=\]

Answer 10

-12

Answer 11

Yes!

Answer 12

But if you haven't been studying complex numbers, maybe \(i\) is not supposed to be the imaginary unit,
in which case you should just leave your answser as \(12i^2\)

Answer 13

ok.. i have 1 last question. someone gave me the answer but i wanted to how how to do it. could you help me one last time?

Answer 14

ok!

Answer 15

than you so so so much!