化简(X平方-5/X-1 +1 )乘以X的 3次方-1/X平方-2X 除以(X+3)
问题描述:
化简(X平方-5/X-1 +1 )乘以X的 3次方-1/X平方-2X 除以(X+3)
TNND 百度林数学符号这么难打
答
x-4√x +1=0
x-4√x +4-3=0
(√x-2)^2=3
√x=2+√3或√x=2-√3
x=7+4√3或x=7-4√3
[(x^2-5)/(x-1)+1]*[(x^3-1)/x^2-2x]/(x+3)
=(x^2+x-6)/(x-1)*[(x-1)(x^2+x+1)/x(x-2)]/(x+3)
=[(x-2)(x+3)(x-1)(x^2+x+1)]/[x(x-1)(x-2)(x+3)]
=(x^2+x+1)/x
=x+1+1/x
当x=7+4√3时,
原式=7+4√3+1+7-4√3
=15
当x=7-4√3+1+7+4√3
=15