共50条信息
下列运算正确的是 ( )
下列各式中运算错误的是( )
\({{x}^{2}}+x+1={{x}^{2}}+(\)___________\()\);\(3{{x}^{2}}-2x{{y}^{2}}+2{{y}^{2}}=3{{x}^{2}}-(\)__________\()\)
\((1)7x-\)\( \dfrac{1}{2}\left[x- \dfrac{1}{2}\left(x-1\right)\right]= \dfrac{2}{3}\left(x-1\right) \)
\((2)\) \(\dfrac{x-3}{0.5}-\dfrac{x+4}{0.2}=1.6\)
\((3)\dfrac{1}{2}\{\dfrac{1}{3}[\dfrac{1}{4}(\dfrac{1}{5}x-1)-6]+4\}=1\)
化简求值:
\((1)-\left( {{x}^{2}}-1 \right)+2\left( {{x}^{2}}-2x-\dfrac{1}{2} \right)\),其中\(x=-2\);
\((2)\left( 4{{a}^{2}}-5ab+{{b}^{2}} \right)-\left( 2{{a}^{2}}-3ab+3{{b}^{2}} \right)\),其中\({{a}^{2}}-{{b}^{2}}=5\),\(ab=2\);
有一根铁丝长为\(a\)米,第一用去了一半的\(1\)米,第二次用去了剩余部分的一半多\(1\)米,这根铁丝还剩余________米.
化简\((\)\(x\)\(―2)^{2}+(\)\(x\)\(+1)(\)\(x\)\(―1)\)
计算:
\((2)(\)\(x\)\(—1)^{2}—(\)\(x\)\(+1)(\)\(x\)\(—3)\).
已知:\(A=2a^{2}+3ab-2a-1\),\(B=-a^{2}+ab-1\).
\((1)\)求\(3A+6B\).
\((2)\)若\(3A+6B\)的值与\(a\)的取值无关,求\(b\)的值.
进入组卷