If a+b>a−b, which of the following must be true? (A) a>b (B) a=b (C) a> 0 (E) b > 0

(E) b > 0

Step-by-step explanation:

a+b > a-b

Subtracting a on both sides,

a+b-a > a-b-a

b > -b

Adding b on both sides,

b+b > b-b

2b > 0

b > 0

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

step-by-step explanation:

what are the statements? and what do you mean by "216 2 1 6"?