The formula C = 2πr means:

circle is equal to 2 times pi times ray:

How do you use the additive inverse to evaluate an expression that uses subtraction in a full sentence

What is the axis of symmetry of the function f(x)=-(x+ 9)(x-21)

There are three bags: a (contains 2 white and 4 red balls), b (8 white, 4 red) and c (1 white 3 red). you select one ball at random from each bag, observe that exactly two are white, but forget which ball came from which bag. what is the probability that you selected a white ball from bag a?