Verified answer

(4y^4)/y = 4y^3

(4y^3)/(b^4) * (5b^2)/6y = 4/6 * 5 * (y^3)/y * 1/b^4 * b^2

10/3 * y^2 * 1/b^2

(10y^2)/(3b^2)

there are two ways to simplify this.

You can multiply every thing out first, and cancel at the the end.

Or you can cancel before you multiply.

I think method 1 my be easiest right now

4y^4/(b^4)(y) * 5b^2 / 6y = 20b^2y^4/ (6b^4y^2) Now work with cancelling

20/6 = 10/3

b^2/b^4 = 1/b^2

y^4 / y^2 = y^2

put the terms together and you get

(10y^2) / (3b^2)

10y^2 / 3b^2 why?