a, $\frac{x}{3}$ = $\frac{-14}{6}$
=> $\frac{x}{3}$ = $\frac{-7}{3}$
=> x = -7
b, $\frac{2}{3}$ . /x/ - 15 = -7
=> $\frac{2}{3}$ . /x/ = -7 + 15
=> $\frac{2}{3}$ . /x/ = 8
=> /x/ = 8 : $\frac{2}{3}$ = 12
=> /x/ = 12
=> $\left \{ {{x=12} \atop {x=-12}} \right.$
c, $(x-3)^{2}$ + 10 = 26
=> $(x-3)^{2}$ = 16
=> $\left \{ {{x - 3 = 4} \atop {x - 3 = -4}} \right.$
=> $\left \{ {{x = 7} \atop {x = -1}} \right.$
