Use a truth table to determine whether the argument is valid or invalid. This is due soon, need help please!

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).

Haley buys 9 pounds of apples for $3. how many pounds of apples can she buy for $1?

What is the radius of a circle with an area of 78.5 cubic inches? use 3.14 for pie