$6\mathrm{.}28$ For the circuits in Fig. P$6\mathrm{.}28,$ assume that the transistors have very large $\backslash (\backslash$beta $\backslash ).$ Some measurements have been made on these circuits, with the results indicated in the figure. Find the values of the other labeled voltages and currents.

$($a$)$

$($b$)$

$($c$)$

$($d$)$

Figure P$6\mathrm{.}28$