Conjugations of verbs for the formal "you" in Spanish are the same as for the subjects el and ella; in present tense, they usually end in -a.
The option you have checked is in past tense ("I bought this"); the present tense conjugation is compra.
Usted compra esto.
Again, the conjugation of verbs for the formal "you" in present tense almost always end in the letter "a"; the correct conjugation is estudia.
Usted estudia matemáticas.
