-x^2+4=x^2-4
2x^2-8=0
x^2=4
x= ± 2
[m]S= ∫ ^{2}_{-2} (-x^2+4-(x^2-4))dx= ∫ ^{2}_{-2} (-x^2+4-x^2+4)dx= ∫ ^{2}_{-2} (8-2x^2)dx=8\cdot x-2\cdot \frac{x^3}{3})|^{2}_{-2}=[/m]
[m]=8\cdot 2-2\cdot \frac{2^3}{3}-(8\cdot (-2)-2\cdot \frac{(-2)^3}{3}=16-\frac{16}{3}=\frac{32}{3}[/m]