Did i do this right i dont get the last part i now thats the answer but how did i do an we're i'd i go wrong

Danielle earns a 7.25% commission on everything she sells at the electronics store where she works. she also earns a base salary of $750 per week. what were her sales last week if her total earnings for the week were $1,076.25?

Ammonia molecules have three hydrogen atoms and one nitrogen atom.how many of each atom arein five molecules of ammonia

In the polynomial below, what number should replace the question mark to produce a difference of squares? x2 + ? x - 36