I really suck at Rational Expressions. Im looking all over youtube

>>161870
(3x^7/7x^5)/(15x/14x^3)
Convert it into a multiply by turning the divisor upside down:
(3x^7/7x^5)*(14x^3/15x)
Multiply the two tops and the two bottoms:
(3x^7*14x^3)/(7x^5*15x)
Remember that when you multiply the same number to different powers, that's the same as adding the powers together:
(21x^10)/(105x^6)
Multiply the top and bottom by x^-6
21x^4/105x^0
=21x^4/105
Multiply the top and bottom by 1/21
x^4/5
=1/5*x^4

Now leave this place and don't come back til your eighteenth birthday.

>>161881
I'm 19. I'm brushing up on my math skills before heading to college.

But thanks, anyway.

>>161870
It's actually (2/5)x^4
Reduce your variables before doing all the shit with numbers to avoid having arithmetic errors like >>161881

>>161895
>Reduce your variables before doing all the shit
Have [3,7] or [14,15] now got GCDs greater than 1?

>>161908
I meant to say cancel variable and reduce your fractions via cross multiplication afterwards. For example:
(3x^7/7x^5)/(15x/14x^3) = ((3x^2)/7)*((14x^2)/15)
At this point you can cross cancel (If you don't know what that is, look it up; It's very useful).
((3x^2)/7)*((14x^2)/15) = (x^2)*((2x^2)/5)
All that's left is to just multiply out.
(x^2)*((2x^2)/5) = (2/5)x^4

>>161929
Cross canceling* not cross multiplication.