Subject with x (7)

I believe the answer is:

algebra

(Other definitions for algebra that I've seen before include "Maths with letters representing numbers" , "branch of learning" , "Form of maths" , "A garble (anag) - branch of mathematics" , "Symbolic maths" .)

I've seen this clue in the Universal.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.