Are these right?
xy - 3x - 8y + 24
(3x-y)-(8y+24)
8y+24
4x^2 + 20x + 5y +xy
36x+(5y+x)
36x-5y
I don't think so it's right.Your question xy-3x-8y+24 is itself the answer.It cannot be further calculated bcause it doesn't have the terms containing the same variables.
If you are factoring then no. Using the commutative and associative properties I can rewrite the equation:
xy - 3x - 8y +24
xy -8y -3x +24
y(x-8) -3(x-8) -factor by grouping
(x-8)(y-3) factor out the (x-8)
Sorry forgot to answer the second one for you. You use the same techniques.
4x^2+20x+5y+xy
4x^2+20x+xy+5y
4x(x+5)+y(x+y)
(x+5)(4x+y)