The variable z varies jointly with x and y. Also, z = -75 when x = 3 and y = -5. What equation describes this variation?

What is the constant of variation?
k =
When x = 1 and y = –2, z =

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).

The sum of two numbers is 12 and their difference is 18 what are the two numbers

The coordinates of vortex a’ are (8,4) (-4,2) (4,-,4) the coordinates of vortex b’ are (6,6)(12,-,12)(12,12) the coordinates of vortex c’ are(-2,,12)(4,12)(12,-4)