Find a ⋅ b
a = 7i - 4j, b = 4i + 3j

28i^2 + 5ij - 12j^2

Step-by-step explanation:

(7i-4j)(4i+3j)

7i times 4i is 28i^2

7i times 3j is 21ij

-4j times 4i is -16ij

-4j times 3j is -12j^2

In equation it looks like this:

28i^2+21ij-16ij-12j^2

Simplify 21ij and -16ij

21ij-16ij is 5ij

So the answer is:

28i^2 + 5ij - 12j^2

Hope this helps!

c

step-by-step explanation:

1. sometimes

2.   never

3   .08c = 7.50+.05c   250 pages

step-by-step explanation:

1.   sometimes

the theoretical probability of rolling a 1 is 1/6.   perhaps you got really lucky and never rolled a 1   in those 60 times.   your experimental probability is 0.   or perhaps you rolled a 1   20 times.   your experimental probability is 20/60 is 1/3.     it really just depends on how you rolled in that experiment.

2.   never

the probability of the event occurring is 1.   that is being 100 % sure it will happen.   that is the maximum amount of confidence we have.

3.   no customer card cost:   .08 times number of pages

customer card cost:   7.50 + .05 times number of pages

we want to find when it costs the same amount, so we will set these equal

let c = number of pages

.08c = 7.50+.05c

subtract .05c from each side

.08c-.05c = 7.5+.05c-.05c

.03c=7.5

divide each side by .03

.03c/.03 = 7.5/03

c =250  

the cost is the same at 250 pages