m/(x-1)+n/(x+2)=2x+7/橘拆(x-1)(x+2)
[m(x+2)+n(x-1)]/(x-1)(x+2)=(2x+7)/旦芦(x-1)(x+2)
(m+n)x+(2m-n)=2x+7
x对应系数相等所以
m+n=2
2m-n=7
解得m=3,n=-1
祝学业进步模伍带
重写后就是:
m/(x-1) + n/(x+2) = (2x+7)/[(x-1)(x-2)]
我想问左边是(x+2)右边嫌则是(x-2),有没吵侍有错芹碰棚?
m=3,n=-1
左边通分得出M+N=2,2M-N=7