#h(x)# is just a way of writing "a function (call it h) in x", meaning whatever is on the other side of the equation. Given a particular value (-2) you just put it into the equation and solve it.
#h(x)=−(5/3)|x|+6#
#h(x)=−(5/3)|-2|+6# ; #h(x)=−(5/3)*2+6#
#h(x)=−(10/6)+6# ; #h(x)=−(10/6)+36/6#
#h(x)= 26/6# ; #h(x)= 13/3# or 4.33