Evaluate the expression below for x = 4.
3x + 2x - 81 - 12

List the elements of the set in roster notation. (enter empty or ∅ for the empty set.) {x | x is a letter in the word hippopotamus}

Find the roots of the equation below. x^2 - 6 + 9 = 0

How do you use the elimination method for this question? explain, because i really want to understand!