Could someone please help me with these couple questions? Instructions on how to do the first two would be great, but for 3 and 4 I know how to do them but I'm not getting the right answers.

1. Determine a quadratic function f(x)=ax²+bx+c whose graphy passes through the point (2,19) and that has a horizontal tangent at (-1,-8).

2. For what values of x do the curves y=(1+x³)² and y=2x6 (6 is an exponent on the x) have the same slope?

3. Differentiate y= (1+√x / x2/3 )³, where 2/3 is an exponent on that x in the denominator.

4. Differentiate y= (√(1-x²) / 1-x ).

Thanks a ton!!!