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Math 017 Materials With Exercises

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Lesson 5__________________________________________________________________________________Topics: Multiplication of algebraic expressions; The Distributive Law; Factorization of a commonfactor; Factorization of 1; Simplification of algebraic fractions with the use of factorization.__________________________________________________________________________________This section is about the Distributive Law, the law that relates addition to multiplication. In manycases, it allows us to rewrite the product of expressions as a sum or the sum of expression as a product.The Distributive LawIf 5 girls and 7 boys get 2 cookies each, then the girls get 2 5 10cookies, the boys get 27 14cookies, so the total number of cookies they all receive is25 271014 24Alternatively, one can find the number of cookies by adding the number of girls and boys first,5 7 12and then since each of the children gets 2 cookies, together they get2(5 7) 212 24This property is called The Distributive Law. In general,The Distributive Lawa(b c) ab aca(b c) ab acTo remove parentheses from the expression of the formfactor outside parentheses by each term inside parentheses.a(b + c) or a(b − c), multiply theExample 5.1 Use the Distributive Law to remove parentheses in the following expressions.2a) x(2 x )b) ( x 2y)c) a( b c d)Solution:2212a) x( 2 x ) x 2 x x 2x x3 2x xb) ( x 2y) 1( x 2y) 1x 12y x 2yc) The expression inside the parentheses should be treated not as a sum of threeterms but as a sum of two ( b c)and d , that is b c d ( b c) d . We can thenapply the Distributive Law a(b c d) a((b c) d) a(b c) adIf we apply the Distributive Law once again, this time to a( b c), we geta( b c d) a((b c) d) a(b c) ad ab ac ad .Thus a( b c d) ab ac ad .50

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