Yup, this would be a question I would ask to students in 7th to 9th grade. 7th if they were very bright and 9th for an average student. It is basic algebra and requires understanding of fractions and the 4 basic math functions which usually doesn’t happen until 6th grade.
I’m glad I’ve still got enough smarts for 9th grade algebra. I’ve always been horrible at math, but self study with a calculus book and a little patience and training really helped me get over some of the rough spots I hated about math in high school.