The function f(x) = 2x + 3 is is defined on the interval [0, 4].

(a) Graph In (b)–(e), approximate the area A under from to as follows: 

(b) Partition [0, 4] into four subintervals of equal length and choose u as the left endpoint of each subinterval. 

(c) Partition [0, 4] into four subintervals of equal length and choose u as the right endpoint of each subinterval. 

(d) Partition [0, 4] into eight subintervals of equal length and choose u as the left endpoint of each subinterval. 

(e) Partition [0, 4] into eight subintervals of equal length and choose u as the right endpoint of each subinterval. 

(f) What is the actual area A?