学校の成績は関係ない
- Your grades from school don't matter.
- Your grades don't matter.
- Your grades are irrelevant.
- Your grades don't have anything to do with this.
学校の成績 = grades from school or grades
関係ない = irrelevant, unrelated
学生時代の成績と、ビジネスで成功する才能は関係ない
- The grades you got from school and your ability to succeed in business have nothing to do with each other.
アメリカ合衆国 
