共50条信息
用配方法证明:
\((1)-x^{2}+6x-10\)的值恒小于零;
\((2)4x^{2}-12x+10\)的值恒大于零.
\((2)\)\((7+4\sqrt{3}){{(2-\sqrt{3})}^{2}}+(2+\sqrt{3})(2-\sqrt{3});\)
先化简,再求值:\((3x+2)(3x-2)-5x(x+1)-{{(x-1)}^{2}}\),其中\(x^{2}-x-2018=0\).
设\(x_{1}\),\(x_{2}\)是一元二次方程\(x^{2}-2x-3=0\)的两根,则\(x\rlap{_{1}}{^{2}}+x\rlap{_{2}}{^{2}}=(\) \()\)
方程\(2{{(x-1)}^{2}}=(x+\sqrt{3})(x-\sqrt{3})\)化为一般形式是________.
计算:
\((1)(-\dfrac{1}{5}a^{3}x^{4}-\dfrac{9}{10}a^{2}x^{3})÷(-\dfrac{3}{5}ax^{2})\);
\((2)(2x-y)(4x\)\({\,\!}^{2}\)\(-y\)\({\,\!}^{2}\)\()(2x+y)\);\((3)[(x+y)\)\({\,\!}^{2}\)\(-(x-y)\)\({\,\!}^{2}\)\(]÷2xy\).
已知\(a=\sqrt{2}+1\),\(b=\sqrt{2}-1\),求下列代数式的值:
\((1){{a}^{2}}+ab+{{b}^{2}}\)
\((2) \dfrac{b}{a}+ \dfrac{a}{b} \)
请你先化简,再选取一个你喜欢的数代入并求值:\( \dfrac{{x}^{2}-4x+4}{{x}^{2}-1}÷\left( \dfrac{3}{x+1}-1\right) \)
进入组卷