1) Fill in the blanks. Main Idea: When you simplify a fraction, you rewrite it so that 1 is the only common factor of the numerator and denominator. How to Simplify a Fraction Example: 15 18 Step 1: Factor the numerator and |Factors of 15:1, 5, 15 denominator. Factors of 18: 1, 2, 6,9, 18 Step 2: Find the greatest GCF: common factor (GCF) of the numerator and denominator. (The greatest factor they both have.) Step 3: Divide the numerator and 15 _ 15 +3 denominator by that GCF. 18 18 +32) Fill in the blanks. Main Idea: Simplifying a rational expression is just like simplifying a fraction. How to Simplify a 2-1 Rational Expression Example: X+X Step 1: Factor the x2 -1 (X +1)1 numerator and x+ X x( x +1) denominator. Step 2: Find the GCF: greatest common factor (GCF) of the numerator and denominator. Step 3: Divide the x2 -1 (x+1)(x- 1) numerator and x+X x(x +1) denominator by that GCF. x3 - 1 * + X Step 4: Identify the x- -1 X-1 x-values that make where x # or *+ X X the expression undefined. (Be sure to include the GCF you factored out!)