Please answer thank you !

Step-by-step explanation:

The questions are asking you whether the calculation of each needs to be exact or an estimate. An estimate is used when the final value needs to be close to what is needed but is ok if it surpasses the needed value. Exact values are used when the final value needs to be exact and cannot be over or under the needed value or it will cause errors. Therefore, the answers are the following...

1. exact

2. estimate

3. exact

4. estimate

5. exact

6. exact

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

29.5977692753

step-by-step explanation: