Question

Hey guys I need help with a few questions. Here is the first. Let u = <-5, -9>, v = <6, 8>. Find -8u - 2v.

Answer 1

\[\Large\bf\sf u=<-5,\;-9>\qquad\implies\qquad 8u=8<-5,\;-9>\]\[\Large\bf\sf 8u=<-5\cdot8,\;-9\cdot8>\]
Distrbute the 8! :U
Oh I should have distributed a -8 I guess -_-

Answer 2

\[\Large\bf\sf -8u\quad=\quad<40,\;72>\]Understand how I got my -8u? :o

Answer 3

I think so, but i dont understand the 40,72 because it isn't one of the options. here are the options <52, 88>

<-8, 2>

<112, -28>

<28, 56>

Answer 4

No we've got more work to do silly :U
That's only about 1/3 of the problem so far.

Answer 5

oh alright whats next :P

Answer 6

\[\Large\bf\sf v=<6,\;8>\]\[\Large\bf\sf -2v=<-2\cdot6,\;-2\;8>\]So what do you get for your -2v? :D

Answer 7

-2v=<-12,-28>?

Answer 8

I think thats right

Answer 9

@zepdrix u there bro?

Answer 10

Ahhhh sorry got busy for a min there :U

Answer 11

Woops I made a typo, you're supposed to multiply the -2 and 8.\[\Large\bf\sf -2v=<-2\cdot6,\;-2\cdot8>\]

Answer 12

\[\Large\bf\sf -2v=<-12,\;-16>\]