Here is the entire calculation for a similar function:

f(x) = 3x² + 4x

For this function, we have:

f(x+h) - f(x) h	=	3(x+h)2 + 4(x+h) - (3x2 + 4x) h
	=	3(x2 + 2xh + h2)+ 4(x+h) - (3x2 + 4x) h
	=	3x2 + 6xh + 3h2+ 4x + 4h - 3x2 - 4x h
	=	6xh + 3h2 + 4h h	Cancel terms
	=	h[6x + 3h + 4] h	Factor h
	=	6x + 3h + 4	Cancel h

Enter this as 6*x + 4 + 3*h

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