Which expression is equivalent to 4 sqrt 16x^11y^8/ 81x^7y^6 assume x> 0 and y=0

One interpretation of your intent would be as follows:

                 16x^11y^8

Find 4 √ []. Is that what you meant?

                   81x^7y^6

                                                                4*x^5*√x*y^4

If so, then the correct result would be 4

                                                                  9*x^3*√x*y^3

and this could be reduced to:

       4*x^5 * y^4 * √(x)     4*x^2*y

4 =

      9*x^3*y^3 √(x)               9

if you need , reply with more info. u.

step-by-step explanation: