Around the 2:30 mark of the video, it says to do 1/4 - 1/2 + 2/3, but because x^2/3 is in the denominator, it should be subtracted, so the calculation should be 1/4 - 1/2 - 2/3 or x^(-11/12) = 1/x^11/12.
In this lesson on rational exponents, we are given examples of working with radicals and fractional exponents. We use the properties of exponents and simplify expressions by only writing with positive exponents. We also learn to change from radical notation to rational to simplify each radical. By the end of the lesson, we are able to write solutions in both exponential and radical form.
Part 4 shows examples working with radicals and fractional exponents.
More free YouTube videos by Julie Harland are organized at http://yourmathgal.com