What is the slope of a line that passes through 5,15 and 6,11?

This is about circle theorems. someone asap : (

Need match the functions with correct transformation. f(x) = -3x f(x) = |x-1|+3 f(x) = √(x+3) 1/2x² f(x) = (x+1)²-3 4|x| 1. compress by a factor of 1/2 2. stretch by a factor of 4 3. shift to the left 3 4. shift to the left 1 5. shift up 3 6. reflection

For a function f(x), a) if f(7) = 22 then f^-1(22) = b) f^-1(f(c)) =