Just a footnote: じゃねえか is a very colloquial form of ではないか. // It's like the abbreviation of "is it not?' in English. // Is it not? → isn't it? → ain' t it ? // ではないか　→　じゃないか　→ じゃねえか.

It's the same meaning with 'じゃないか？" which nearly mean like 'isn't it?' in English. It's not that negative, but just put more extremely feeling into the word like sometime say 'やべぇ' instead of 'やばい'