Please help will give brainliest!!

Two lines that do not intersect are skew. always sometimes or never

This is my question~~ ( r ^ 4 - 2r ^ 3 - 23 r ^ 2 - 4r - 32)÷(r+4) ~~ i must use long division to solve it : / i was wondering if anyone world like to solve it. and if so, share step-by-step explanations! you! ❤

1) prove that 731^3−631^3 is divisible by 100 2) prove that 99^3−74^3 is divisible by 25