A product is the answer that you get when you multiply numbers together. So for this problem, you have 2 groups to multiply together. Since I cannot show a square or cubed x, I will put an x2 for x squared and an x3 for x cubed. You have to multiply each number in the first parentheses by each number in the second parentheses. Then combine any like sets.
(8x-3)(x2-4x+8)
8x3-32x2+64x-6x+12x-24
8x3-32x2+70x-24
So the answer is 8x cubed minus 32x squared plus 70x minus 24. Whew! That's a long one. Hope I didn't miss anything.
Û = (-1, -1, -1)
^v = (2, 3, -5)
^v - û = (2 + 1, 3 + 1, -5 + 1) = (3, 4, -4)
Half way from ^v to ^(v - u) = ((3 - 2)/2, (4 - 3)/2, (-4 + 5)/2) = (1/2, 1/2, 1/2)
Halfway from û to ^v = ((2 + 1)/2, (3 + 1)/2, (-5 + 1)/2) = (3/2, 2, -2)
The required vector ^w = ((3/2 - 1/2), (2 - 1/2), (-2 - 1/2)) = (1, 1/2, -5/2)
Euler's formula tells us that


Suppose we subtract the two. This eliminates the cosine terms.

Divide both sides by

and you're done.