$12\mathrm{.}7$ and $12\mathrm{.}8$ Draw the shear and bending$-$moment diagrams for the beam and loading shown, and determine the maximum absolute value $\backslash (($a$)\backslash )$ of the shear, $\backslash (($b$)\backslash )$ of the bending moment.

Fig. P$12\mathrm{.}8$