1. State the correct form for the partial fractions
Let (2x+1)(x−1)27x+8=2x+1A+x−1B+(x−1)2C
2. Form the basic algebraic identity
7x+8=A(x−1)2+B(2x+1)(x−1)+C(2x+1)
3. Find the value of $C$ by substituting $x = 1$
Substitute x=1:
7(1)+8=C(2(1)+1)
15=3C
C=5
4. Find the value of $A$ by substituting $x = -\frac{1}{2}$
Substitute x=−21:
7(−21)+8=A(−21−1)2
29=A(−23)2
29=49A
A=2
5. Find the value of $B$ by substituting $x = 0$
Substitute x=0, A=2, and C=5:
8=A(−1)2+B(1)(−1)+C(1)
8=2−B+5
8=7−B
B=−1
答案2x+12−x−11+(x−1)25