Multiplying Algebraic FractionsDate: 11/05/2002 at 00:57:22 From: Lizet Subject: Multiplying and dividing algebraic fractions Perform the indicated operation and simplify: x^2+8x+7 x^2+2x-3 -------- . ---------- x^2-1 x^2+10x+21 The answer is 1, but I don't know how to get it. Date: 11/05/2002 at 19:08:35 From: Doctor Ian Subject: Re: Multiplying and dividing algebraic fractions Hi Lizet, The key is to factor the quadratic expressions, so you can get binomials that cancel each other out. Let's look at an operation similar to yours: x^2-5x+6 x^2+6x+5 = ---------- * ---------- x^2-x-2 x^2+2x-15 (x-2)(x-3) (x+1)(x+5) = ---------- * ---------- (x+1)(x-2) (x-3)(x+5) (x+1)(x-2)(x-3)(x+5) = -------------------- (x+1)(x-2)(x-3)(x+5) = 1 Does this help? - Doctor Ian, The Math Forum http://mathforum.org/dr.math/ |
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