Question

Find the dot product, a • b.

a = 6i + 5j, b = -5i + 4j

Answer 1

<-30, 20>?

Answer 2

Same as do

http://www.mathskey.com/question2answer/16283/find-a-%E2%8B%85-b-a-7-4-b-3-5

Answer 3

so is this your question?
(6i+5j)(-5i+4j)

Answer 4

yes

Answer 5

so expand

Answer 6

(6i+5j).(-5i+4j)
(6)(-5)+(5)(4)=-30+20=-10

Answer 7

-30i^2 +10ji-10ji +9j^2

Answer 8

=-30i^2+9j^2