d(x) = g(x) - f(x)
= (3/16·x^2 - 3) - (- 1/8·x^2 + 2)
= 3/16·x^2 - 3 + 1/8·x^2 - 2
= 5/16·x^2 - 5
D(x) = 5/48·x^3 - 5·x
A1 = ∫ (-5 bis -4) d(x) dx = D(-4) - D(-5) = 40/3 - 575/48 = 65/48
A2 = ∫ (-4 bis 4) d(x) dx = D(4) - D(-4) = -40/3 - 40/3 = -80/3
A = |A1| + |A2| = 65/48 + 80/3 = 1345/48 = 28.02