What is an algebraic expression for "21 more than n"?

The diameter of a circular chip is doubled to use in a new board game. the area of the new chip will be

Determine the mean and variance of the random variable with the following probability mass function. f(x)=( 729divided by 91) (1 divided by 9) superscript x baseline comma x equals 1,2,3 round your answers to three decimal places (e.g. 98.765).

Consider 6x2 + 6x + 1. which term immediately tells you that this expression is not a perfect square trinomial? justify your answer