I need help with number 9

D

Step-by-step explanation:

We can safely assume we are dealing with an arithmetic scale because the type of scale isn't mentioned anywhere. The more right a point is on the scale, the higher its value is. We are given two points of the scale: 3 and 4. Because the scale is arithmetic, we know that 3.8 must lie on 4/5s of the length between 3 and 4 to the right of 3, which is exactly where point D is.

correct choice is b

step-by-step explanation:

when you calculate the average rate of change of a function, you are finding the slope of the secant line between the two points. for the function the average rate of change from point to point can be calculated as

to find the average rate of change from day 2 to day 10, note that at day 2, 8 houses were sold, so a(2,8) and at day 10, 2 houses were sold, so b(10,2). thus,

for this case we have by definition, if two lines are perpendicular, then the product of their slopes is -1.

then, given the following line:

so,

we are looking for m_ {2}:

then, the line is given by:

we find "b" replacing the given point:

finally, the equation is:

option c