[m]S=\int ^{3}_{2}(x+6-x^2)dx=(\frac{x^2}{2}+6x-\frac{x^3}{3})|^{3}_{2}=(\frac{3^2}{2}+6\cdot 3-\frac{3^3}{3})-(\frac{2^2}{2}+6\cdot 2-\frac{2^3}{3})=13,5-\frac{34}{3}[/m]
4.
[m]S=\int^{4}_{0}(4t+6t^2)dt=(4\frac{t^2}{2}+6\frac{t^3}{3})|^{4}_{0}=(2\cdot4^2-0)+3\cdot 4^3=32+192=224[/m]