The rectangles in the graph illustrates a left endpoint Riemann sum for f(x)=−(x^2/4)+2x on the interval [3,7].

Question

The value of this left endpoint Riemann sum is?

The rectangles in the graph illustrates a right endpoint Riemann sum for f(x)=−(x^2/4)+2x on the interval [3,7].
The value of this right endpoint Riemann sum is