- #1
lubo
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Homework Statement
For the equation shown below:
x2+2x+3 / (x2+9)(X-3) = Ax+B/(x2+9) + C/(x-3)
Find A, B and C
Homework Equations
The Attempt at a Solution
C = 1
B = 2
A = ?
Find C which = 1 by putting x=3 and working out x2+2x+3/(x2+9),
then multiply out equation to find A and B
x2+2x+3 = C(X2+9) + (Ax+B)/(X-3)
Combine terms to give:
x2+9+Ax2-3Ax+Bx-3B
= x2(1+A)+ x(B-3A) + 9 -3B
if coefficients = 0 then x2 = 0 then A = -1
9-3B = 3 therefore B = 2
B-3A = 0 therefore A = 2/3 but I think this answer is wrong? I now have 2 answers for A?
Any ideas please and thanks.