which of the five labeled points is the most influential with respect to a regression of trade-in value versus miles driven

Given the two similar triangles, how do i find the missing length? if a=4, b=5, and b'=7.5 find a'

Suppose that the price p, in dollars, and the number of sales, x, of a certain item follow the equation 4 p plus 4 x plus 2 pxequals56. suppose also that p and x are both functions of time, measured in days. find the rate at which x is changing when xequals2, pequals6, and startfraction dp over dt endfraction equals1.5.

(60 points) explain this in detail