How to write a linear function with the values f(3)=-4 f(5)=-4

A linear function: f: R ---> R, f(x) = ax + b;

f(3) = -1 <=> 3a + b = -1;

f(5) = -4 <=> 5a + b = -4;

Then, b = - 1 - 3a;

We obtain 5a + (-1-3a) = -4;

5a - 1 - 3a = -4;

2a - 1 = -4;

2a = -3;

a = -3/2;

b = - 1 + 9/2;

b = 7/2;

f(x) = (-3/2)x + 7/2;

Step-by-step explanation:

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

what i would say the best answer is a. 40.5