Tính giá trị biểu thức
\(A=\frac{\left(0,6\right)^5}{\left(0,3\right)^6}\) \(B=\frac{-1^3}{3^3+3\times6^2+6^3}\)
\(C=\frac{2\times5^5\times4^5}{20^4\times5^4}\) \(D=\left(\frac{-10}{3}\right)^3\times\left(\frac{-6}{5}\right)^3\)
\(E=2\div\left(\frac{1}{2}-\frac{2}{3}\right)^{^2}\) \(G=\left(\frac{4}{5}-\frac{3}{2}\right)^2\div\left(1-\frac{1}{4}+\frac{2}{3}\right)\)
Tính giá trị biểu thức :
\(\left[\frac{4}{5}+\frac{4}{10}\right]\times5-\frac{17}{5}.\)
\(\frac{6}{5}\)x 5 - \(\frac{17}{5}\)= \(\frac{30}{5}\)- \(\frac{17}{5}\)=\(\frac{13}{5}\)
ta có:4/5*5+4\10*5)-17/5
=20/5+20/10)-17/5
=50/10-17/5
=10/1+(-17)/5
=-33/5
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Tìm giá trị của các biểu thức sau:
a)\(\frac{45^{10}.5^{20}}{75^{15}}\)
b)\(\frac{\left(0,8\right)^5}{\left(0,4\right)^6}\)
c)\(\frac{2^{15}.9^4}{6^6.8^3}\)
a.
\(\frac{45^{10}\times5^{20}}{75^{15}}=\frac{\left(3^2\times5\right)^{10}\times5^{20}}{\left(3\times5^2\right)^{15}}=\frac{3^{20}\times5^{10}\times5^{20}}{3^{15}\times5^{30}}=3^5=243\)
b.
\(\frac{\left(0,8\right)^5}{\left(0,4\right)^6}=\frac{\left(0,8\right)^5}{\left(0,4\right)^5}\times\frac{1}{\left(0,4\right)}=\left(\frac{0,8}{0,4}\right)^5\times\frac{1}{\frac{4}{10}}=2^5\times\frac{5}{2}=2^4\times5=16\times5=80\)
c.
\(\frac{2^{15}\times9^4}{6^6\times8^3}=\frac{2^{15}\times\left(3^2\right)^4}{\left(2\times3\right)^6\times\left(2^3\right)^3}=\frac{2^{15}\times3^8}{2^6\times3^6\times2^9}=3^2=9\)
Chúc bạn học tốt ^^
\(1.\)Tính
\(a)\frac{120^3}{40^3};\frac{390^4}{130^4};\frac{3^2}{0,375^2}\)
\(2.\)Tính giá trị các biểu thức sau :
\(a)\frac{45^{10}.5^{20}}{75^{15}}\) ; \(b)\frac{\left(0,8\right)^5}{\left(0,4\right)^6}\) ; \(c)\frac{2^{15}.9^4}{6^6.8^3}\)
1. sai dấu nhé
2.a, \(\frac{45^{10}.5^{20}}{75^{15}}=\frac{\left(3^2.5\right)^{10}.5^{20}}{\left(5^2.3\right)^{15}}=\frac{3^{20}.5^{30}}{5^{30}.3^{15}}=3^5=243\)
b, \(\frac{\left(0,8\right)^5}{\left(0,4\right)^6}=\frac{\left(\frac{4}{5}\right)^5}{\left(\frac{2}{5}\right)^6}=\frac{\left(\frac{2}{5}\cdot2\right)^5}{\left(\frac{2}{5}\right)^6}=\frac{\left(\frac{2}{5}\right)^5\cdot2^5}{\left(\frac{2}{5}\right)^5\cdot\frac{2}{5}}=2^5\div\frac{2}{5}=32\cdot\frac{5}{2}=80\)
c, \(\frac{2^{15}.9^4}{6^6.8^3}=\frac{2^{15}.3^8}{2^6.3^6.2^9}=\frac{2^{15}.3^2}{2^{15}}=3^2=9\)
Tính giá trị biểu thức sau:
\(\frac{45^{10}\times5^{20}}{75^{15}}\)
Trình bày rõ ràng giúp mình nha, cảm ơn!
\(\frac{45^{10}\times5^{20}}{75^{15}}=\frac{3^{20}\times5^{10}\times5^{20}}{3^{15}\times5^{30}}=3^5=243\)
Tính giá trị biểu thức:
a. \(\frac{20^5\times5^{10}}{100^5}\)
b. \(\frac{\left(0,9\right)^5}{\left(0,3\right)^6}\)
c. \(\frac{6^3+3\times6^2+3^3}{-13}\)
d. \(\frac{4^6\times9^5+6^9\times120}{8^4\times3^{12}-6^{11}}\)
e. \(\left(2^{-1}+3^{-1}\right):\left(2^{-1}-3^{-1}\right)+\left(2^{-1}\times2^0\right)\times2^3\)
f. \(\left(\frac{-1}{3}\right)^{-1}-\left(\frac{-3}{5}\right)^6+\left(\frac{1}{2}\right)^2:2\)
a. \(\frac{20^5.5^{10}}{100^5}\)
\(=\frac{20^5.\left(5^2\right)^5}{100^5}\)
\(=\frac{20^5.25^5}{100^5}\)
\(=\frac{500^5}{100^5}\)
\(=\left(\frac{500}{100}\right)^5\)
\(=5^5=3125\)
b. \(\frac{\left(0,9\right)^5}{\left(0,3\right)^6}\)
\(=\frac{\left(0,9\right)^5}{\left(0,3\right)^5.0,3}\)
\(=\left(\frac{0,9}{0,3}\right)^5.\frac{1}{0,3}\)
\(=3^5.\frac{1}{0,3}\)
\(=810\)
c. \(\frac{6^3+3.6^2+3^3}{-13}\)
\(=\frac{\left(3.2\right)^3+3.\left(3.2\right)^2+3^3}{-13}\)
\(=\frac{3^3\left(2^3+2^2+1\right)}{-13}\)
\(=\frac{3^3.13}{-13}\)
\(=\left(-3\right)^3\)
\(=-27\)
2. Tính giá trị của biểu thức:
A = \(\frac{25^3\times5^5}{6\times5^{10}}\)
\(A=\frac{25^3.5^5}{6.5^{10}}\)
\(A=\frac{\left(5^2\right)^3.5^5}{6.5^{10}}\)
\(A=\frac{5^6.5^5}{6.5^{10}}\)
\(A=\frac{5^{11}}{6.5^{10}}\)
\(A=\frac{5}{6}\)
(Dùng phương pháp giảm ước)
\(=\frac{\left(5^2\right)^3.5^5}{6.5^{10}}\)
\(=\frac{5^6.5^5}{6.5^{10}}\)
\(=\frac{5^{11}}{6.5^{10}}\)
\(=\frac{5}{6}\)
VẬY \(A=\frac{5}{6}\)
A = \(\frac{25^3x5^5}{6x5^{10}}=\frac{\left(5^2\right)^3x5^5}{6x5^{10}}=\frac{5^6x5^5}{6x5^{10}}=\frac{5^{11}}{6x5^{10}}=\frac{5}{6}.\)
1.Tính giá trị biểu thức
a)\(\frac{8^{20}+4^{20}}{4^{25}+64^5}\)
b)\(\frac{45^{10}\times5^{20}}{75^{15}}\)
2.Tìm x,b
\((x-2)^{2012}+|b^2-9|^{2014}=0\)
Bài 1:
a)
\(\frac{8^{20}+4^{20}}{4^{25}+64^5}=\frac{(2^3)^{20}+(2^2)^{20}}{(2^2)^{25}+(2^6)^{5}}=\frac{2^{60}+2^{40}}{2^{50}+2^{30}}=\frac{2^{40}(2^{20}+1)}{2^{30}(2^{20}+1)}=2^{10}\)
b)
\(\frac{45^{10}.5^{20}}{75^{15}}=\frac{(3^2.5)^{10}.5^{20}}{(3.5^2)^{15}}=\frac{3^{20}5^{30}}{3^{15}.5^{30}}=\frac{3^{20}}{3^{15}}=3^5\)
Bài 2:
Ta thấy $(x-2)^{2012}=[(x-2)^{1006}]^2\geq 0$ với mọi $x\in\mathbb{R}$
$|b^2-9|^{2014|\geq 0$ với mọi $b\in\mathbb{R}$ (tính chất trị tuyệt đối)
Do đó để tổng của chúng bằng $0$ thì:
\((x-2)^{2012}=|b^2-9|^{2014}=0\)
\(\Leftrightarrow \left\{\begin{matrix} x-2=0\\ b^2-9=0\end{matrix}\right.\Leftrightarrow \left\{\begin{matrix} x=2\\ b=\pm 3\end{matrix}\right.\)
Vậy.......
\(\frac{1}{3\times5}+\frac{1}{5\times7}+\frac{1}{7\times9}+...+\frac{1}{\left(2x+1\right)\left(2x+3\right)}=\frac{15}{96}\)
\(\frac{1}{3.5}+\frac{1}{5.7}+\frac{1}{7.9}+...+\frac{1}{\left(2x+1\right).\left(2x+3\right)}=\frac{15}{96}\)
\(2.\left(\frac{1}{3.5}+\frac{1}{5.7}+\frac{1}{7.9}+...+\frac{1}{\left(2x+1\right).\left(2x+3\right)}\right)=2.\frac{15}{96}\)
\(\frac{2}{3.5}+\frac{2}{5.7}+\frac{2}{7.9}+...+\frac{2}{\left(2x+1\right).\left(2x+3\right)}=\frac{5}{16}\)
\(\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+...+\frac{1}{2x+1}-\frac{1}{2x+3}=\frac{5}{16}\)
\(\frac{1}{3}-\frac{1}{2x+3}=\frac{5}{16}\)
\(\frac{1}{2x+3}=\frac{1}{3}-\frac{5}{16}\)
\(\frac{1}{2x+3}=\frac{1}{48}\)
=> 2x + 3 = 48
=> 2x = 48 - 3
=> 2x = 45
=> x = 45/2
