Order of Operations for Solving EquationsDate: 10/12/95 at 17:26:18 From: Richard Seguin Subject: Multiplying Binomials... How would you multiply a question like this? -2(x-y)^2? Date: 11/28/95 at 17:45:45 From: Doctor Rob Subject: Re: Multiplying Binomials... Hi Richard, The principle to follow when doing algebraic manipulations like the above is to follow the "Order of Operations," which can be remembered as: P.E.M.D.A.S. 1. Parentheses 2. Exponents 3. Multiplication 4. Division 5. Addition 6. Subtraction In other words, do what is possible within parentheses first, then exponents, then multiplication and division (it doesn't matter what order), and then addition and subtraction (again, it doesn't matter what order). So say you're given a problem like this: Evaluate 6(x - 4)^2 Step 1: Nothing to do in parentheses, so evaluate the binomial 6(x - 4)^2 = 6(x^2 - 8*x +16) [recall that (x - y)^2 = x^2 - 2xy + y^2] Step 2: Apply the distributive property of multiplication [a(b+c) = ab + ac] 6(x^2 - 8*x +16) = 6*x^2 - 6*8*x + 6*16 Step 3: Do the multiplication = 6*x^2 - 48*x + 96 I hope this helps you with your problem. Work it through and see if you get the answer -2x^2 + 4xy - 2y^2. -Doctor Rob, The Geometry Forum |
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