what is the instantaneous rate of change of the function below f(x)= (x-4)(x-1)/x^2-2x+1 at x=3 with a step size of change in x =0.1?

X/y + 4y/x divided by x/y - 2y/x explain as in depth as you can how you simplfied the fractions. i don't know where to start on this : /

Set $r$ is a set of rectangles such that (1) only the grid points shown here are used as vertices, (2) all sides are vertical or horizontal and (3) no two rectangles in the set are congruent. if $r$ contains the maximum possible number of rectangles given these conditions, what fraction of the rectangles in set $r$ are squares? express your answer as a common fraction.

Amayoral candidate would like to know her residents’ views on a tax on sugar drinks before the mayoral debates. she asks one thousand registered voters from both parties. these voters are an example of a census population convenience sample simple random sample