Please help will mark crown

Choose the correct classification of 3x4 − 9x3 − 3x2 + 6. 5th degree polynomial 4th degree polynomial 9th degree polynomial 24th degree polynomial

The polynomial 10x3 + 35x2 - 4x - 14 is factored by grouping. 10x3 + 35x2 - 4x - 14 5x )-20 what is the common factor that is missing from both sets of parentheses?

X/y + 4y/x divided by x/y - 2y/x explain as in depth as you can how you simplfied the fractions. i don't know where to start on this : /