We'll decompose the fraction into elementary irreducible
fractions:
(5x-4)/(x-2)(x+3) = A/(x-2) +
B/(x+3)
We'll calculate LCD of the 2 fractions from the right
side.
The LCD is the same with the denominator from the left
side.
LCD = (x-2)(x+3)
We'll multiply
both sides by (x-2)(x+3) and the expression will become:
(5x-4) =
A(x+3) + B(x-2)
We'll remove the
brackets:
5x - 4 = Ax + 3A + Bx -
2B
We'll combine like terms form the right
side:
5x - 4 = x(A+B) +
(3A-2B)
Comparing we'll get:
5 =
A+B
-4 = 3A-2B
We'll use the symmetric
property:
A+B = 5 (1)
3A-2B = -4
(2)
We'll multiply (1) by 2:
2A+2B = 10
(3)
We'll add (3) to (2):
2A+2B+3A - 2B
= 10-4
We'll eliminate like terms:
5A =
6
We'll divide by 5:
A =
6/5
We'll substitute A in (1):
A+B =
5
6/5 + B = 5
We'll subtract 6/5 both
sides:
B = 5 - 6/5 => B = (25-6)/5 => B =
19/5
The given fraction written as partial fractions
is: (5x-4)/(x-2)(x+3) = 6/5(x-2) + 19/5(x+3), where
6/5(x-2) and
19/5(x+3) are partial
fractions.
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