Advanced Math/functions

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Expert: Sherry Wallin - 11/16/2009


Question
If f(x-3)=x^3+2x^2+7x+1, determine f(x)
I tried to divide x^3+2x^2+7x+1 by x-3, but my answer was x^2+5x+22+67/(x-3).  So, I multiplied the entire equation by x-3 and got x^3+2x^2+7x+1.  But, when I graphed both of the equations, they were different.  What did I do wrong?

Answer
Hi Katharine~
    What you want is a function that when you evaluate it at (x-3) you get x^3+2x^2+7x+1. Shift our x over from x- 3 t x by adding 3: (x+3)^3 +2(x+3)^2 +7(x+3) + 1. When you find that result then evaluate it at x-3. You should get x^3+11x^2+46x + 67 from the first step and then put your x-3 into this function and you will get x^3+2x^2+7x+1.

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Sherry Wallin

Expertise

I can answer most questions up through Calculus and some in Number Theory and Abstract Algebra.

Experience

I have had my Bachelor's Degree since 1987 and have been a teacher since 1988. I earned my Masters Degree in Mathematics May 2010. I have been teaching at the same community college since 2002.

Education/Credentials
I have taught 12 years at the community college level, medical college, and technical college as well as a high school instructor and alternative education instructor and charter school instructor.

Awards and Honors
Master's GPA 3.56 Bachelor's GPA 3.34 Post grad work not degree related GPA 4.0

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