取り組まなければ

if (someone) doesn't tackle, unless (someone) tackles

→ 取り組む

取り take, pick up + 組ま team up, form a team + なけれ Negative conditional + ば Conditional (if/when)

verb · conditional Rare #39,324

if (someone) doesn't tackle, unless (someone) tackles

JA: この問題に取り組まなければ、解決できません。

EN: If you don't tackle this problem, you won't be able to solve it.

Conjugation of 取り組む

Conditional

取り組まなければ

I have a lot of things I need to work on.

I have important work at the company that I need to devote myself to.

These problems must be approached carefully.

I have to work hard at physics.