\(\dfrac{d}{dx}[x^{n}] = nx^{n - 1}\)
\(ex. a\)
\(\dfrac{d}{dx}[x^{3}] = 3x^{3 - 1} = 3x^{2}\)
\(ex. b\)
\(\dfrac{d}{dx}[5x] = (1)5x^{1-1} = 5x^{0} = 5\)
\(ex. c\)
\(\dfrac{d}{dx}[\dfrac{5}{4}x^{2}] = (2)\dfrac{5}{4}x^{2 - 1} = \dfrac{10}{4}x^{1} = \dfrac{10}{4}x\)
