Consider the region below (x) = 5 - x, above the x-axis, and between x = 0

Consider the region below ƒ(x) = 5 - x, above the x-axis, and between x = 0 and x = 5. Let xi be the midpoint of the ith subinterval.
(a) Approximate the area of the region using five rectangles.
(b) Find ∫₀⁵ (5 - x) dx by using the formula for the area of a
triangle.