Set X is the set of all multiples of 6 between 15 and 70. Which set is equivalent to set X?
A. {6, 12, 18, 24,...}
B. {6, 12, 18, ...,66}
C. {18, 24, 30, 36,...}
D. {18, 24, 30, ..., 66}
E. {18, 24, 30, ..., 70}

D

Step-by-step explanation:

we have 2 conditions

1. to be a multiple of 6

2. to be between 15 and 70

A and B are not correct because have numbers les than 15

C is not correct because the numbers keep on going passed 70

E is not correct because 70 is not a multiple of 6

D is correct because has both conditions meet

the value of v.w= -12.

step-by-step explanation:

we are given three vector r,v and w as:

r = < 5, -5, -2> ; v = < 2, -8, -8> ; w = < -2, 6, -5>

we know that r,v and w could also be represented as:

r=5i-5j-2k

v=2i-8j-8k

and w= -2i+6j-5k

where i,j and k are the unit vectors of x,y and z-axis respectively.

also we know that it has the following property:

i.i=1 ; j.j=1; k.k=1

and i.=j.i=i.k=k.i=j.k=k.j=0

i.e. when we multiply two vectors or we find it's dot product we need to only multiply the components of x coordinates with each other; y with each other and z with each other.

hence, v.w= (2i-8j- -2i+6j-5k)

                  = 2×(-2)+(-8)×(6)+(-8)×(-5)

                  = -4-48+40

                  = -12

hence, v.w= -12