x2−3x+2=A(x−3)2 +B(x−4)(x−3)+C(x−4)... (i) This is an identity so, true for every value of x. On putting x=3 in Eq. (i), we have C=−2 On putting x=4 in Eq. (i), we have A=6 On putting x=0 in Eq. (i) and A=6 and C:=−2, we have B=−5 Now, A+B+C=6−5−2=−1