(a) Use six rectangles to find left-hand, right-hand, and midpoint estimates for the area under the given graph of $f$ from $x = 0$ to $x = 12$.

$L_6 \approx$

$R_6 \approx$

$M_6 \approx$

? Underestimate Overestimate Exact  1. (b) Is $L_6$ an underestimate or overestimate of the exact area?

? Underestimate Overestimate Exact  1. (c) Is $R_6$ an underestimate or overestimate of the exact area?

(d) Which of the numbers $L_6,$ $R_6,$ or $M_6$ appears to be the best estimate?

A. $M_6$
B. $L_6$
C. Impossible to tell.
D. $R_6$