Pics included! will give brainliest! show work and explain

I assume you know about the dot product, and that for two vectors and , the angle between them satisfies

Then the vectors are parallel if the angle between them is 0 or 180 degrees (0 or pi radians), which would make or , respectively.

Part A)

Then the angle between is such that

so these vectors are parallel ("antiparallel", more specifically, which means they are parallel but point in opposite directions).

Part B) involves the same computations:

has the same components but differing by sign and order, as ; its magnitude remains the same, though:

which is neither 0 nor pi, which means these vectors are not parallel.

38.5

step-by-step explanation:

lets say, first number = r

second number = 3r+7

total = 49

(r)+(3r+7)= 49

4r+7 = 49

4r = 42

r = 42/4

r= 10.5

3r+7 = 3(10.5)+7 = 38.5

hope this

the image of (6, 9) under a dilation is (4, 6). the scale factor is