\(\frac{\mathrm d y}{\mathrm d x} = 3x^{2} - 2x + 1\)

\(y = \int_{1} ^{3} (3x^{2} - 2x + 1) \mathrm d x\)

\(y = [x^{3} - x^{2} + x]_{1} ^{3}\)

= \([3^{3} - 3^{2} + 3] - [1^{3} - 1^{2} + 1]\)

= \(21 - 1 = 20\)