TO SOLVE EQUATIONS WITH RATIONAL EXPONENTS YOU NEED TO… Isolate the variable To undo a rational exponent, raise both sides of the equation by the reciprocal of that rational exponent. REMINDERS: You CAN’T take the square root of a negative number. You CAN take the cube root of a negative number When you take a square root of a number, you need to consider both positive and negative values. If the number isn’t a perfect square or cube, leave it in its radical form for a more exact answer. Check Solution.