6 - 7 please would help me with my test a lot thank you!

6. Evaluate the following: 2h-h3 a. lim h - 0 b. lim x2-2x+1 h - 1 x-1 7. The function f (x) = =x3 - 5x2 + ax + 1, where a is a real number, has a stationary point at: x = 2 a. Find the value of a b. Find the coordinates and nature of all stationary points