Can anyone help me with these questions? Please

1. ac - bc + ad - bd
2. xy - 3x - 8y + 24
3. 4x2 + 20x + 5y +xy
4. 48x2y + 20xz +12xy + 5z

is the 4x2 4 times 2 or 4x to the power of two or 4 times x times 2?
same question with 48x2y.

its to the 2nd power