2/3√81-5

To simplify the expression, we can start by simplifying the cube root of 81. The cube root of 81 is 4, since 4 cubed equals 64.

So we have: 2/3 * 4 - 5

Next, we multiply the numerator (2) by the cube root (4) and simplify: 2/3 * 4 = 8/3

Now we can rewrite the expression: 8/3 - 5

To subtract these fractions, we need a common denominator, which in this case is 3. So we multiply the numerator and denominator of 5 by 3: 8/3 - 5 * 3/3 = 8/3 - 15/3

Now that we have a common denominator, we can subtract the fractions: 8/3 - 15/3 = (8 - 15) / 3 = -7/3

Therefore, the simplified expression is -7/3.