The key to general division is to determine the simplest common denominator of several fractions, and the steps are as follows:

1. Factorize the denominator of each fraction;

2. Take the least common multiple of denominator coefficient;

3. All the letters or factors based on letters should be taken;

4. The factor with the same letter or the power of the factor with the letter takes the largest exponent;

5. Multiply all the above formulas to get the simplest common denominator;

6. Multiply the numerator and denominator of the atomic formula by an appropriate algebraic expression to simplify the denominator of each subformula to the simplest common denominator.

For example, this question: 1-x? =( 1-x)( 1+x+x？ ), then the simplest common denominator is (1-x? );

Then the first decimal part is (1-x? ) can be calculated.

1/( 1-x)-3/( 1-x？ )

=( 1+x+x？ )/( 1-x)( 1+x+x？ )-3/( 1-x)( 1+x+x？ )

=( 1+x+x？ -3)/( 1-x)( 1+x+x？ )

=(x+x？ -2)/( 1-x)( 1+x+x？ )

=(x+2)(x- 1)/( 1-x)( 1+x+x？ )

=-( 1-x)(x+2)/( 1-x)( 1+x+x？ )

=-(x+2)/( 1+x+x？ )

=(-x-2)/( 1+x+x？ )