Black Friday: lifetime access is on a special offer in the app, until November 30. Black Friday: special offer on lifetime access, until November 30. Download
수학에서 미지수는 문제를 푸는 데 중요한 역할을 합니다.suhakeseo mijisuneun munjeleul puneun de jungyohan yeokhal-eul hamnida.In mathematics, an unknown variable plays an important role in solving problems.