1.For what values ofxdoes the graph off(x) =x³+3x²+x+15

have a horizontal tangent? (Enter your answers as a comma-separated list.)

x=

2.Find the parabola with equationy=ax²+bx

whose tangent line at(1,0)

has equationy=3x3.

y=

3.Differentiate the function.

y=6x²+8x+8/

sqrtx