Question

How do you simplify `5i*-i`?

Answer 1

`5i * -i = color(red)(5)`

Explanation:

`5i * -i`
`color(white)("XXX")=color(blue)(5)color(cyan)(i)color(orange)(-1)color(green)(i)`

`color(white)("XXX")=(color(blue)(5) * (color(orange)(-1))) xx (color(cyan)(i) * color(green)(i))`

`color(white)("XXX")=(-5) xx (-1)`

`color(white)("XXX")=+5`

Answer 2

5

Explanation:

The product is `5ixx-i=-5i^2`

`color(orange)"Reminder"`

`color(red)(bar(ul(|color(white)(a/a)color(black)(i^2=(sqrt(-1))^2=-1)color(white)(a/a)|)))`

`rArr-5i^2=-5xx-1=5`