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5 x ( \(\dfrac{-5}{2}\) )2 + \(\dfrac{2}{15}\) x \(\sqrt{\dfrac{9}{4}}\) - ( -2022)0 + | -0,25|
= 5 x \(\dfrac{25}{4}\) + \(\dfrac{2}{15}\) x \(\dfrac{3}{2}\) - 1 + 0,25
= \(\dfrac{125}{4}\) + \(\dfrac{1}{5}\) - ( 1 - 0,25)
= 31,25 + 0,2 - 0,75
= 31,45 - 0,75
= 30,7
a/ S = ( - 2/3 + 1) - (7/5 - 0,2) + )7/15 - 1 + 4/3) = - 2/3 + 1 - 7/5 + 1/5 +7/15 - 1 + 4/3 = 2/3 - 6/5 + 7/15 = 10/15 - 18/15 + 7/15 = - 1/15.
b/ S = 0,25 - 9- (- 3/4) - [ - 7/3 + (-9/2)] - 5/6 = 1/4 - 9 + 3/4 + 7/3 + 9/2 - 5/6 = - 8 + 14/6 + 27/6 - 5/6 = - 8 + 6 = - 2
b: \(\Leftrightarrow\left\{{}\begin{matrix}x-7y=0\\11x-5=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=\dfrac{5}{11}\\y=\dfrac{x}{7}=\dfrac{5}{77}\end{matrix}\right.\)
Lời giải:
a. Bạn cần viết đề bằng công thức toán để đề được rõ ràng hơn.
b. Ta có:
$(7y-x)^{2020}\geq 0$ với mọi $x,y$
$|5-11x|^{2021}\geq 0$ với mọi $x,y$
Do đó để tổng của chúng bằng $0$ thì:
$(7y-x)^{2020}=|5-11x|^{2021}=0$
$\Leftrightarrow x=\frac{5}{11}; y=\frac{5}{77}$
\(M=\left(\dfrac{\dfrac{2}{5}-\dfrac{2}{9}+\dfrac{2}{11}}{\dfrac{7}{5}-\dfrac{7}{9}+\dfrac{7}{11}}-\dfrac{\dfrac{1}{3}-\dfrac{1}{4}+\dfrac{1}{5}}{\dfrac{7}{6}-\dfrac{7}{8}+\dfrac{7}{10}}\right)\times\dfrac{2022}{2021}\)
\(M=\left(\dfrac{\dfrac{178}{495}}{\dfrac{623}{495}}-\dfrac{\dfrac{17}{60}}{\dfrac{119}{120}}\right)\times\dfrac{2022}{2021}\)
\(M=\left(\dfrac{2}{7}-\dfrac{2}{7}\right)\times\dfrac{2022}{2021}\)
\(M=0\times\dfrac{2022}{2021}\)
M=0
\(a,=\dfrac{3}{2}-\dfrac{5}{6}:\dfrac{1}{4}+\sqrt{\dfrac{1}{4}-\dfrac{1}{2}}=\dfrac{3}{2}-\dfrac{10}{3}+\sqrt{\dfrac{1}{2}}=-\dfrac{11}{6}+\dfrac{\sqrt{2}}{2}=\dfrac{-33+3\sqrt{2}}{6}\)
\(b,=-\dfrac{4}{3}\cdot\dfrac{9}{2}+\dfrac{13}{12}\cdot\left(-\dfrac{8}{13}\right)=6-\dfrac{2}{3}=\dfrac{16}{3}\\ c,=\dfrac{1}{4}-\left(-\dfrac{1}{6}:4-8\cdot\dfrac{1}{16}\right)=\dfrac{1}{4}-\left(-\dfrac{1}{24}-\dfrac{1}{2}\right)\\ =\dfrac{1}{4}-\dfrac{13}{24}=-\dfrac{7}{24}\\ d,=\dfrac{3^{11}\cdot5^{11}\cdot5^7\cdot3^4}{5^{18}\cdot3^{18}}=\dfrac{1}{3^3}=\dfrac{1}{27}\)
\(=\dfrac{25}{4}+\dfrac{2}{15}\cdot\dfrac{3}{2}-1+\dfrac{1}{4}=\dfrac{26}{4}-1+\dfrac{1}{5}=\dfrac{22}{4}+\dfrac{1}{5}=\dfrac{114}{20}=\dfrac{57}{10}\)