。・・・・・・。
Math. The determinant section is homework, but... I really can't keep up with it...
Literal
Math. Determinant [attributive-の] place [subject-が] homework [as-に] has-become-[contracted-ってる][explanatory-んだけど]... somehow I [as-for-には] can't-keep-up-[ren'yōkei-なくて]...
A dejected student complaint, trailing off twice. ~のところ ('the X part / section of') is a casual way to refer to a specific portion. 行列式 ('determinant') is the linear-algebra term. なってる is the contracted form of なっている, and ~んだけど is the explanatory ~のだけど softened by contraction. どうも here is the adverbial 'somehow, for some reason.' ついていける is the potential form of ついていく ('to keep up with'). The double ellipsis … captures hesitation and dejection.