If x is a number that is 7 more than y, how do you express x as a function of y?
a. x = f(y) = 7 + x
b. x = f(y) = 7 + y
c. y = f(x) = 7x
d. y=f(x) =y-7
e. y=f(x) = 7+y

B.

Step-by-step explanation:

We are given x is a number that is 7 more than y.

This means when you add 7 to y you get x.

So the equation for this is 7+y=x.

We want x as a function of y. So we want to replace x with f(y).

This means we have the function 7+y=f(y) or f(y)=7+y by symmetric property of equality.

Your answer is B.

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: