Question

已知x+1分之m+x-1分之n等于x的平方-1分之1-3x 求mn

Answer 1

m/(x+1)+n/(x-1)=(1-3x)/(x-1) [m(x-1)+n(x+1)]/(x-1)=(1-3x)/(x-1) mx-m+nx+n=1-3x (m+n)x+(n-m)=1-3x m+n=-3,n-m=1 m=-2,n=-1