The graph of y=f(x) is shown below. find all the values of x where f(x)=8

The value of x when f(x) = 8 according to the graph is; 4.

According to the graph;

We must plot a line of the equation; y = 8.

Ultimately, the x coordinates of this point is 4 and hence, the value of x when f(x) = 8 is 4.

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x  =  4

Step-by-step explanation:

Find 8 on the y-axis.  Draw a horizontal line through y =8.  Determine the x value for which the graph intersects this horizontal line y = 8.  It is x = 4

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