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三、解答题(共60分)
21.(12分)计算:
(1)$\sqrt{2}+3\sqrt{2}-5\sqrt{2}$;
(2)$(-2)^3×\sqrt{(-4)^2}+\sqrt[3]{(-4)^3}×(\frac{1}{2})^2-\sqrt{9}$;
(3)$\sqrt[3]{8}+\sqrt{(-2)^2}-\sqrt{\frac{1}{4}}$;
(4)$\sqrt[3]{-27}-\sqrt{0}-\sqrt{\frac{1}{4}}+\sqrt[3]{0.125}+\sqrt[3]{1-\frac{63}{64}}$.
21.(12分)计算:
(1)$\sqrt{2}+3\sqrt{2}-5\sqrt{2}$;
(2)$(-2)^3×\sqrt{(-4)^2}+\sqrt[3]{(-4)^3}×(\frac{1}{2})^2-\sqrt{9}$;
(3)$\sqrt[3]{8}+\sqrt{(-2)^2}-\sqrt{\frac{1}{4}}$;
(4)$\sqrt[3]{-27}-\sqrt{0}-\sqrt{\frac{1}{4}}+\sqrt[3]{0.125}+\sqrt[3]{1-\frac{63}{64}}$.
答案
21. (1)$-\sqrt{2}$ (2)$-36$ (3)$\dfrac{7}{2}$ (4)$-2\dfrac{3}{4}$
22. (6分)解下列方程组：
(1)$\begin{cases}2x+3y=7, \\x=-2y+3;\end{cases}$
(2)$\begin{cases}2s+3t=-1, \\4s-9t=8.\end{cases}$
(1)$\begin{cases}2x+3y=7, \\x=-2y+3;\end{cases}$
(2)$\begin{cases}2s+3t=-1, \\4s-9t=8.\end{cases}$
答案
22. (1)$\begin{cases} x=5, \\ y=-1. \end{cases}$ (2)$\begin{cases} s=\dfrac{1}{2}, \\ t=-\dfrac{2}{3}. \end{cases}$
