Three rational expressions are given: .

MATHEMATICS · Multi-part · AP · AP Precalculus · Polynomial and Rational Functions · Polynomial and Rational Functions

Problem

Three rational expressions are given: p(x)=xx−3,q(x)=x+5x2−9,r(x)=x2−1x2−4x+3\displaystyle p(x)=\frac{x}{x-3},\quad q(x)=\frac{x+5}{x^2-9},\quad r(x)=\frac{x^2-1}{x^2-4x+3}. (i) Determine the set of excluded values for each of p(x)p(x), q(x)q(x) and r(x)r(x) separately. (ii) Using your results from part (i), write the domain of p(x)+q(x)p(x)+q(x). (iii) Find the domain of the product p(x) q(x) r(x)p(x)\,q(x)\,r(x), clearly indicating all values that must be excluded and giving reasons for each exclusion.

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