当x=3时,求下列式子的值∶3x+2/x^2-x-2+(1-1/x+1)÷(1+1/x-1)
问题描述:
当x=3时,求下列式子的值∶3x+2/x^2-x-2+(1-1/x+1)÷(1+1/x-1)
过程。。。。另外在加一道题已知m/x^2--y^2=2xy--y^2/x^2--y^2=x-y/x+y则m=?
答
原式=(3x+2)/(x-2)(x+1)+(x+1-1)/(x+1)÷(x-1+1)/(x-1)=(3x+2)/(x-2)(x+1)+x/(x+1)÷x/(x-1)=(3x+2)/(x-2)(x+1)+(x-1)/(x+1)=(3x+2+x²-3x+2)/(x+1)(x-2)=(x²+4)/(x+1)(x-2)=(9+4)/(4×1)=13/4还有一道