∵ x2+3x−4x2=(x−1)(x+4)x2=1+(x−1)(x+4)4−3x Let (x−1)(x+4)−3x+4=x−1A+x+4B(x−1)(x+4)−3x+4=(x−1)(x+4)A(x+4)+B(x−1)−3x+4=x(A+B)+(4A−B) On compiaring the coefficients on both sides A+B=−3 and 4A−B=4B=−3−A ⇒ 4A−(−3−A)=45A=1A=51 ⇒ B=−3−51=5−16 ∴ x2+3x−4x2=1+5(x−1)1+5(x+4)−16