Does anyone know how too do this i need

Find the sum of 4x^{2} -4+6 and -7^{2} +3x+1

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).

An equation of the line tangent to y=x^3+3x^2+2 at its point of inflection is