Question

rewrite the rational expression with the given denominator for 7/20y = ?/40y^3

Answer 1

7            ?

----     =  ------

20 y     40 y^3

to get the denominators to match we need to multiply by 2y^2

what we do to the bottom we do to the top

7*2 y^2

14y^2

7            14y^2

----     =  ------

20 y     40 y^3