PLEASE HELP ME Prove that for any natural of n the value of the expression:
(3n+1)^2-(3n-1)^2 is divisible by 12

34 cup. a serving of vegetable soup is 23 cup. the restaurant sold 20 servings of chicken noodle soup and 18 servings of vegetable soup. how many more cups of chicken noodle soup did they sell than cups of vegetable soup?

What is the distance from zero if a quadratic function has a line of symmetry at x=-3 and a zero at 4

Add, subtract, multiply, or divide as indicated. list any restrictions for the variable(s) and simplify the answers when possible. 1) x-2 / x+5 + 3x / 2x-1 2) x+6 / x-6 - x^2 / x+6 3) x+9 / x-4 + x+2 / x^2-11x+28 4) x / x^2-64 + 11 / 2x^2+11x-40 5) 5 / x + 11 / x-3 - x-4 / x^2+2x-15