Question

数学，剩下题谢谢

Answer 1

20. 接下去解

原式=[(x+2)(x-2)/x(x-2)² -x(x-1)/x(x-2)²] × x/(x-4)
=[(x²-4-x²+x)/x(x-2)²]× x/(x-4)
=(x-4)/x(x-2)² ×x/(x-4)
=1/(x-2)²
=1/(1-2)²
=1/1
=1

Answer 2

[(x+2)/(x²-2x)-(x-1)/(x²-4x+4)]÷(x-4)/x 其中 x=1
=[(x+2)/x(x-2)-(x-1)/(x-2)²]*x/(x-4)
=[(x²-4-x²+x)/x(x-2)²]*x/(x-4)
=[(x-4)/x(x-2)²]*x/(x-4)
=1/(x-2)²
=1/(1-2)²
=1/(-1)²
=1