Question

AB分之(BC减A平方)加上BC分之(AC减B平方)加上AC分之(AB减C平方)

Answer 1

1、=（bc^2-a^2c+a^2c-ab^2+ab^2-ac^2）/abc=(b-a)c^2/abc=(b-a)c/ab

2、=10/(x+4)(x-1)-(x+1)(x+4)/(x-1)(x+4)+ (x-1)(x+4)/ (x-1)(x+4)=(10-x^2-5x-4+x^2+3x-4)/ (x-1)(x+4)=(2-2x)/ (x-1)(x+4)=-2(x-1)/ (x-1)(x+4)=-2/(x+4)