共50条信息
已知\(\dfrac{xy}{x+y}={2}\),\(\dfrac{xz}{x+z}={3}\),\(\dfrac{yz}{y+z}={4}\),求\(7x+5y-2z\)的值.
下列命题中正确的是 ( )
当\(m\)取何值时,方程\(x^{2}+mx+m-1=0\)分别适合下列条件:
\((1)\)两根之和等于\(2\);
\((2)\)两根互为倒数;
\((3)\)两根互为相反数;
\((4)\)有一个根为\(0\).
下列正确的有:\(①\)若\(x\)与\(3\)互为相反数,则\(x+3=0\);\(②-\dfrac{1}{2}\)的倒数是\(2\);\(③|-15|=-15\);\(④\)负数没有立方根.
进入组卷