Answer
$\int_{-2}^1 f(x) dx = 48$
Work Step by Step
$\int_{-2}^1 (x^2-6x+12) dx $
$=[\frac{x^3}{3} -\frac{6x^2}{2} + \frac{12x}{1}]_{-2}^1$
$=[\frac{1^3}{3} -(3)1^2 + 12(1)]-[\frac{(-2)^3}{3}-3(-2)^2 + 12(-2)] $
$= [\frac{1}{3} -3+12]-[-\frac{8}{3}-12-24] $
$=[\frac{28}{3}]-[-\frac{116}{3}] $
$=\frac{144}{3} $
$=\boxed{48} $