亚洲激情+欧美激情,无码任你躁久久久久久,我的极品美女老婆,性欧美牲交在线视频,亚洲av高清在线一区二区三区

電子課本網(wǎng) 第78頁

第78頁

信息發(fā)布者:
解:
$\begin{aligned}16x^{2}&=81\\x^{2}&=\frac{81}{16}\\x&=\pm\frac{9}{4}\end{aligned}$
解:
$\begin{aligned}(x - 2)^{2}-25&=0\\(x - 2)^{2}&=25\\x - 2&=\pm5\end{aligned}$
當$x - 2 = 5$時,$x = 7;$當$x - 2 = -5$時,$x = -3。$
解:
$\begin{aligned}(1 + 2x)^{3}-\frac{61}{64}&=1\\(1 + 2x)^{3}&=1+\frac{61}{64}\\(1 + 2x)^{3}&=\frac{125}{64}\\1 + 2x&=\frac{5}{4}\\2x&=\frac{5}{4}-1\\2x&=\frac{1}{4}\\x&=\frac{1}{8}\end{aligned}$
解:
$\begin{aligned}&\sqrt{36}-\sqrt{3}-\vert\sqrt{3}-2\vert+\sqrt[3]{64}\\=&6-\sqrt{3}-(2 - \sqrt{3})+4\\=&6-\sqrt{3}-2+\sqrt{3}+4\\=&8\end{aligned}$
解:
$\begin{aligned}&\sqrt{(-4)^{2}}+\sqrt{2\frac{1}{4}}+\sqrt[3]{3\frac{3}{8}}-\sqrt{3^{2}+4^{2}}\\=&4+\sqrt{\frac{9}{4}}+\sqrt[3]{\frac{27}{8}}-\sqrt{25}\\=&4+\frac{3}{2}+\frac{3}{2}-5\\=&4 + 3-5\\=&2\end{aligned}$
$\sqrt{5}$
解:
因為$2a + 7b + 3$的立方根是$3,$所以$2a + 7b + 3 = 3^{3}=27,$即$2a + 7b = 24;$
因為$3a + b - 1$的算術平方根是$4,$所以$3a + b - 1 = 4^{2}=16,$即$3a + b = 17。$
聯(lián)立方程組$\begin{cases}2a + 7b = 24\\3a + b = 17\end{cases},$
由$3a + b = 17$可得$b = 17 - 3a,$
將$b = 17 - 3a$代入$2a + 7b = 24$得:
$\begin{aligned}2a + 7(17 - 3a)&=24\\2a + 119 - 21a&=24\\-19a&=24 - 119\\-19a&=-95\\a&=5\end{aligned}$
把$a = 5$代入$b = 17 - 3a$得$b = 17 - 3×5 = 17 - 15 = 2。$
因為$9\lt14\lt16,$所以$3\lt\sqrt{14}\lt4,$$\sqrt{14}$的整數(shù)部分$c = 3。$
則$3a - b + c = 3×5 - 2 + 3 = 15 - 2 + 3 = 16,$$3a - b + c$的平方根是$\pm4。$
$3.14,\frac {3}{7}$
$100, -2, 0, -2011$
$-\frac{\pi}{4}, 2.010010001\cdots(每相鄰兩個1之間依次多1個0)$