FInd the area and avearge value by integration
1. Determine the value of f(x)=-5x^3+7x on [-1,2]. 2. Determine the area of region bound by f(x)=-2x^2+x+6 and the x-axis on [0,3]. 3. Determine the area of the region bounded by f(x)=x^2 - 4 and g(x)=x+2 4. Determine the area of the region bounded by f(x)=x+6 and g(x)=-x^2+2 on the interval on [-2, 2]. keywords: