For vectors u=-6i +2k and v=7i-4j, find (-3u)*v.
A) -450
B) -50
C) 108
D) 150
First, we need to find -3u:
-3u = -3(-6i + 2k)
-3u = 18i - 6k
Now we can find the dot product of -3u and v:
(-3u)∙v = (18i - 6k)∙(7i - 4j)
(-3u)∙v = 18*7 + (-6)*(-4)
(-3u)∙v = 126 + 24
(-3u)∙v = 150
Therefore, the answer is D) 150.