Question 1103572
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Your work is fine; and the system of equations you need to solve to finish the problem is easily solved.  The system is obtained by equating the coefficients of each power on the two sides of the equation:<br>
x^3 term: A = 1
x^2 term: B = 0
x term: 16A+C = 0
constant term: 16B+D = 0<br>
Surely you can finish from there; then the result is easy to check by plugging in the values you found for A, B, C, and D.