How do we multiply and divide rational expressions?

Multiplying and Dividing rational expressions are really easy. All you need to remember is to multiply straight across then simplify, simple as that! Like this:

Here you factor the expressions out first than you multiplied straight across. 4x+8 over  x²-25 times x-5 over 5x+10. You take factor each expression and you get 4(x+2) over (x+5)(x-5) times x-5 over 5(x+2). Than you cancel out what the expressions have in common like x+2 and x-5. Multiply straight across and viola! the answer is 4 over 5(x+5).

Dividing rational expressions includes a different step. In order to divide rational expressions you must KCF, which stands for Keep Change Flip. You must keep the first expression change the division sign to a multiplication sign than flip the second expression. Like this:

Here you keep the 2x²y over 3yz and change the division sign to a multiplication sign and flip the expression to 16xd²   over 9y²z. Than you cross out what is in common to simplify the expression and multiply straight across, and there is your answer!




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Sources:

• http://virtualnerd.com/images/Tutorial/Alg1_8_1_4-diagram_thumb-lg.png
• http://www.virtualnerd.com/images/Tutorial/Alg1_08_01_0019-diagram_thumb-lg.png
• http://hotmath.com/help/solutions/genericalg1/7/2/RationalExpressionsandRationalEquations/genericalg1_7_2_RationalExpressionsandRationalEquations_25_605/image062.gif