Question 3&4. Need help asap don't need to involve the steps.

3. Prove the statement is true by using mathematical induction. 13 + 23 + 33 +..... + n3 = n2 (n + 1)2 4 4. A box contain nine red balls and six green balls. Seven balls are selected at random from the box. What is the probability that three of the selected balls will be red and four will be green