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)=−(53)|x|+6
h(x)=−(53)|−2|+6 ; h(x)=−(53)⋅2+6
h(x)=−(106)+6 ; h(x)=−(106)+366
h(x)=266 ; h(x)=133 or 4.33