Question

16. (9 - 61)(4 - 21)36 -24ib. 24 + 42i24 - 42i

Answer 1

`(9-6i)(4-2i)`

We will start with multiplying 9 by 4

`9*4=36`

Then multiply 9 by -2i

`9*-2i=-18i`

then multiply -6i by 4

`-6i*4=-24i`

Then multiply -6i by -2i

`-6i*-2i=12i^2`

The value of i^2 is -1, then multiply 12 by -1

`-6i*-2i=12i^2=12*-1=-12`

Now, we will collect them together

`36-18i-24i-12`

We will add the like terms

`(36-12)+(-18i-24i)=24+(-42i)=24-42i`

The answer is c