Steven has 14 steel balls of equal weight. if he puts 9 of them in one pan of a pan balance and the rest along with a weight of 20 grams in the other pan, the pans balance each other. what is the weight of one steel ball?

What is the effect on the graph of the function f(x)=x when f(x) is replaced with -f(x)+4

Plot the intercepts to graph the equation

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.