Evaluate this indefinite integral: \(\int(3x+5)dx\)

What is the integral of the constant function \(f (x, y) = 5\) over the rectangle \([-2,3]\times[2,4]\)?

Suppose \(\int_{-2}^{2}f(x)dx=4,\int_{2}^{5}f(x)dx=3, \int_{-2}^{5}g(x)dx=2\). Is the following statement true? \(\int_{-2}^{5}(f(x)+g(x))=9\)