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Algebra/Multiplying 2 trinomials

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Expert: Bryan Dettmann - 10/19/2004


Question
Hi, I was curious if you can help me understand how to multiply 2 trinomials by one another.

Answer
first you take the first term of the first trinomial and distribute it to the secound trinomial.  Then do the same with the 2nd and 3rd terms of the first trinomial and collect like terms.

take for instance (x^2+3x+5) and (3x^2+6x+9)

(x^2+3x+5)(3x^2+6x+9)=3x^4+15x^3+40x^2+48x+45

x^2(3x^2+6x+9)+3x(3x^2+6x+9)+5(3x^2+6x+9)
3x^4+6x^3+9x^2+9x^3+18x^2+18x+15x^2+30x+45
3x^4+6x^3+9x^3+9x^2+16x^2+15x^2+30x+18x+45
3x^4+15x^3+40x^2+48x+45

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Bryan Dettmann

Expertise

I can answer questions involving 1. Solving Linear equations 2. Graphing Linear and Qudradic equations 3. Solving Qudradic Equations 4. Solving systems of linear equations 5. Probability 6. Rational expressions 7. Porportions 8. Percents 9. symplifying Radicals 10. basic connections to Geometry 11. exponents 12. Variation 13. Inequalities and anything else related to algebra

Experience

I have taken Algebra 1, Algebra II, Geometry, Pre-Calculus, Calculus and Analytic Geometry 1, and Calculus and Analytic Geometry 2. I am proficiant in Algebra 1 and 2, some geometry, trig, and single variable calculus topics.

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