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1. Tìm x, biết :
a. ( x - \(\frac{3}{4}\)) \(^2\)= 0
=> x - \(\frac{3}{4}\)= 0
=> x = 0 + \(\frac{3}{4}\)
=> x = \(\frac{3}{4}\)
b. ( x + \(\frac{1}{2}\)) \(^2\)= \(\frac{9}{64}\)
=> ( x + \(\frac{1}{2}\)) \(^2\)= ( \(\frac{3}{8}\)) \(^2\)
=> x + \(\frac{1}{2}\)= \(\frac{3}{8}\)
=> x = \(\frac{3}{8}\)- \(\frac{1}{2}\)
=> x = \(\frac{-1}{8}\)
c. \(\frac{\left(-2\right)^x}{16}=-8\)
=> \(\frac{\left(-2\right)^x}{16}=\frac{-8}{1}=\frac{-128}{16}\)
=> ( -2)\(^x\)= -128
=> ( -2 ) \(^x\)= ( -2) \(^7\)
=> x = 7
\(9^8:3^2=3^{16}:3^2=3^{14}\)
\(\frac{45^{10}.5^{20}}{75^{15}}=\frac{\left(5.3^2\right)^{10}.5^{20}}{\left(5^2.3\right)^{15}}=\frac{5^{10}.3^{20}.5^{20}}{5^{30}.3^{15}}=3^5\)
\(\frac{2^{15}.9^4}{6^6.8^3}=\frac{2^{15}.3^8}{2^6.3^6.2^9}=\frac{2^{15}.3^8}{2^{15}.3^6}=3^2=9\)
1) 98 : 32 =(32)8:32=32.8:32=316:32=316-2=314
2) (4510.520)/7515=[(5.23)10.520]/(53)15=(510.23.10.520)/53.15=(530.230)/545=230/515=(22)15/515=(4/5)15
3) (215.94)/(66.83)=[215.(32)4]/[(2.30)....
Bạn làm tương tự
hk tốt nha!!!
a) \(\frac{2}{3a}-\frac{3}{a}=\frac{2}{3a}-\frac{9}{3a}=\frac{-7}{3a}=\frac{7}{15}\Leftrightarrow-3a=15\Leftrightarrow a=-5\)
b)\(2x^3-1=15\Leftrightarrow2x^3=16\Leftrightarrow x^3=8\Leftrightarrow x=2\)
\(\Rightarrow\frac{2+16}{9}=\frac{y-15}{16}=2\Leftrightarrow y-15=32\Leftrightarrow y=47\)
c) \(\left|x\right|=3\Rightarrow\orbr{\begin{cases}x=-3\\x=3\end{cases}}\) rồi xét 2 trường hợp để tính A nhé :)
Bài 1: ĐK của a: \(a\ne0\)
Quy đồng VT ta có: \(\frac{2a-9a}{3a^2}=\frac{7}{15}\)
\(\Leftrightarrow\frac{-7a}{3a^2}=\frac{7}{15}\)
\(\Leftrightarrow-7a.15=3a^2.7\)
\(\Leftrightarrow-105a=21a^2\)
\(\Leftrightarrow-105a-21a^2=0\)
\(\Leftrightarrow a\left(-105-21a\right)=0\)
\(\Leftrightarrow\hept{\begin{cases}a=0\left(l\right)\\-105-21a=0\end{cases}\Leftrightarrow a=-5\left(n\right)}\)
Vậy:..
Luyện tập - Bài 43 SGK tập 1 - Trang 23 - Toán lớp 7 | Học trực tuyến
((3\(^2\)))\(^2\) - ((-5\(^2\)))\(^2\) + ((-2\(^3\)))\(^2\)
= 81 - 625 + 64
= -544+ 64
= -480
2\(^4\) + 8[(-2)\(^2\) :\(\dfrac{1}{2}\)]\(^0\) - 2\(^{-2}\). 4 + (-2)\(^2\)
= 16+ 8.1 - \(\dfrac{1}{4}\). 4 + 4
= 16+ 8- 1+4
= 27
2\(^4\) + 3(\(\dfrac{1}{2}\))\(^0\) + 2\(^{-2}\).8 + [(-2)\(^3\). \(\dfrac{1}{2^4}\)].2 - \(\dfrac{1}{2}\)
= 16 + 3.1 +\(\dfrac{1}{4}\).8 + [(-8).\(\dfrac{1}{16}\)].2 -\(\dfrac{1}{2}\)
= 16 + 3+ 2 + \(\dfrac{-1}{2}\).2- \(\dfrac{1}{2}\)
= 21 + (-1)- \(\dfrac{1}{2}\)
= 20-\(\dfrac{1}{2}\) = \(\dfrac{40}{2}\) - \(\dfrac{1}{2}\)= \(\dfrac{39}{2}\)
\(\dfrac{15^{10}.5^{10}}{75^{10}}\) + \(\dfrac{\left(0,8\right)^5}{\left(0,4\right)^6}\)
= \(\dfrac{\left(15.5\right)^{10}}{75^{10}}\) + \(\dfrac{\left(0,4.2\right)^5}{\left(0.4\right)^6}\)
= \(\dfrac{75^{10}}{75^{10}}\) + \(\dfrac{\left(0,4\right)^5.2^5}{\left(0,4\right)^6}\)
= 1 + \(\dfrac{2^5}{0,4}\) = 1+ 80 = 81
\(\dfrac{2^{13}.9^4}{6^3.8^3}\)
= \(\dfrac{2^{13}.\left(3^2\right)^4}{\left(2.3\right)^3.\left(2^3\right)^3}\) = \(\dfrac{2^{13}.3^8}{2^3.3^3.2^9}\)
= \(\dfrac{2^4.3^5}{2^3}\) = 2.3\(^5\) = 486
đề hình như có gì đó sai sai
đề ko cho biết mọt cái gì hết ngoài biểu thức
=385 nữa mik quên