We want to decompose the given rational function into partial fractions. Since the denominator is (x+1)(x−2)2, we write the decomposition as (x+1)(x−2)2x+4=x+1A+x−2B+(x−2)2C Multiplying both sides by (x+1)(x−2)2, we get x+4=A(x−2)2+B(x+1)(x−2)+C(x+1) −1+4=A(−1−2)2+B(−1+1)(−1−2)+C(−1+1) 3=A(−3)2+0+0 A=93=31 2+4=A(2−2)2+B(2+1)(2−2)+C(2+1) 6=0+0+3C C=36=2 Now, we can pick any other value for x to solve for B. Let's choose x=0. 0+4=A(0−2)2+B(0+1)(0−2)+C(0+1) 4=4A−2B+C Substitute A=31 and C=2: 4=4(31)−2B+2 4=34−2B+2 4−2−34=−2B 2−34=−2B 36−4=−2B 32=−2B B=−22/3=−31 Thus, the partial fraction decomposition is
(x+1)(x−2)2x+4=x+11/3+x−2−1/3+(x−2)22 =3(x+1)1−3(x−2)1+(x−2)22