4 21 Stillv. Simplifying Rational Fun 6.2.1 Study: Rational Expressions Study Guide Algebra II Name Find the vila Date: Use the questions below to keep track of key concepts from this lesson's study activity. 1) Fill in the blanks. A rational expression is a comparison of two polynomials, expressed as a 2) Main Idea: You can find the value of a rational expression if you know the value of the variable. Rule Example To evaluate a rational expression, a Evaluate when x = 2. specific number for every variable in the expression and simplify. +1 3) Main Idea: A rational expression equals zero when its numerator equals zero. Rule Example To find the value or values that makes a rational Find the values of x that make this expression expression equal to zero, find any value that equal to zero: makes the equal to zero. X - 1 (x+1)(x-5) x - 1 =0 X =_ The expression equals zero when x = 4) Main Idea: A rational expression is undefined when its denominator equals zero