Janie is walking in a walk-a-thon to earn money for charity. she walks at a constant rate and for every hour that she walks she makes money. she models her earnings by a linear equation since she is walking at a constant rate. the x-axis shows the amount of time she walks in hours and the y-axis shows the amount of money she earns in tens of dollars. how much will she earn if she walks for four hours? a) $4 b) $8 c) $40 d) $80

D)$80

Step-by-step explanation:

The slope of the graph is 2 units. So for every hour she walks she earns $20. The graph passes through the point (4,8) meaning if she walks for four hours she will earn $80 for charity sorry to say it but im pretty mad

off because of the answer sorry I mean the wrong answer on the bottom so i think everyone deserve to have the right one.

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