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\(S=-2,5+\frac{23}{4}-\left(-3,25+\frac{1}{2}+\frac{13}{2}\right)\)
\(S=-\frac{5}{2}+\frac{23}{4}-\left(-\frac{13}{4}+\frac{1}{2}+\frac{13}{2}\right)\)
\(S=-\frac{5}{2}+\frac{23}{4}-\left(\frac{15}{4}\right)\)
\(S=-\frac{1}{2}\)
\(S=-2,5+\frac{23}{4}-\left(-3,25+\frac{1}{2}+\frac{13}{2}\right)\)
\(S=-2,5+\frac{23}{4}+3,25-\frac{1}{2}-\frac{13}{2}\)
\(S=\frac{23}{4}-2,5+3,25-7\)
\(S=3,25+3,25-7\)
\(S=6,5-7\)
\(S=-0,5\)
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Câu một \(=3^2.\frac{1}{3^5}.\left(3^4\right)^2.\frac{1}{3^3}=3^{10}.\frac{1}{3^8}=3^2=9\)
Câu hai \(=\left(2^2.2^5\right):\left(2^3.\frac{1}{2^4}\right)=\frac{2^7}{\frac{2^3}{2^4}}=2^8=256\)
Chờ chút nhá :D
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Tìm x trong các tỉ lệ thức sau :
\(\left(a\right)3,8\div\left(2x\right)=\frac{1}{4}\div2\frac{2}{3}\)
\(3,8\div\left(2x\right)=\frac{3}{32}\)
\(2x=3,8\div\frac{3}{32}\)
\(2x=40\frac{8}{15}\)
\(x=20\frac{4}{15}\)
\(\left(0,25x\right)\div3=\frac{5}{6}\div0,125\)
\(\left(0,25x\right)\div3=6\frac{2}{3}\)
\(\left(0,25x\right)=6\frac{2}{5}\times3\)
\(\left(0,25x\right)=20\)
\(x=80\)
\(0,01\div2,5=\left(0,75x\right)\div0,75\)
\(0,004=\left(0,75x\right)\div0,75\)
\(0,75x=0,75\times0,004\)
\(0,75x=0,003\)
\(x=0,004\)
\(1\frac{1}{3}\div0,8=\frac{2}{3}\div\left(0,1x\right)\)
\(1\frac{2}{3}=\frac{2}{3}\div\left(0,1x\right)\)
\(\left(0,1x\right)=\frac{2}{3}\div1\frac{2}{3}\)
\(\left(0,1x\right)=\frac{2}{5}\)
\(x=4\)
Dung ko z
![](https://rs.olm.vn/images/avt/0.png?1311)
a ) \(\left(\frac{2}{5}-x\right):1\frac{1}{3}+\frac{1}{2}=-4\)
\(\left(\frac{2}{5}-x\right):\frac{4}{3}+\frac{1}{2}=-4\)
\(\left(\frac{2}{5}-x\right):\frac{4}{3}=-4-\frac{1}{2}\)
\(\left(\frac{2}{5}-x\right):\frac{4}{3}=-\frac{9}{2}\)
\(\frac{2}{5}-x=-\frac{9}{2}.\frac{4}{3}\)
\(\frac{2}{5}-x=-3\)
\(x=\frac{2}{5}-\left(-3\right)\)
\(x=\frac{2}{5}+3\)
\(x=\frac{3}{5}-\frac{15}{5}\)
\(x=-\frac{12}{5}\)
Vay \(x=-\frac{12}{5}\)
b ) \(\left(-3+\frac{3}{x}-\frac{1}{3}\right):\left(1+\frac{2}{5}+\frac{2}{3}\right)=-\frac{5}{4}\)
\(\left(-3+\frac{3}{x}-\frac{1}{3}\right):\left(\frac{15}{15}+\frac{6}{15}+\frac{10}{15}\right)=-\frac{5}{4}\)
\(\left(-3+\frac{3}{x}-\frac{1}{3}\right):\left(\frac{15+6+10}{15}\right)=-\frac{5}{4}\)
\(\left(-3+\frac{3}{x}-\frac{1}{3}\right):\frac{31}{15}=-\frac{5}{4}\)
\(\left(-3+\frac{3}{x}-\frac{1}{3}\right)=-\frac{5}{4}.\frac{31}{15}\)
\(\left(-3+\frac{3}{x}-\frac{1}{3}\right)=-\frac{1}{4}.\frac{31}{3}\)
\(-3+\frac{3}{x}-\frac{1}{3}=-\frac{31}{12}\)
\(-3+\frac{3}{x}=-\frac{31}{12}+\frac{1}{2}\)
\(-3+\frac{3}{x}=-\frac{31}{12}+\frac{6}{12}\)
\(-3+\frac{3}{x}=\frac{-25}{12}\)
\(\frac{3}{x}=\frac{-25}{12}+3\)
\(\frac{3}{x}=\frac{-25}{12}+\frac{36}{12}\)
\(\frac{3}{x}=\frac{5}{6}\)
\(\frac{18}{6x}=\frac{5x}{6x}\)
Đèn dây , bạn tự làm tiếp nhé , de rồi chứ
Bài làm :
Ta có :
\(2,5.\left(-\frac{1}{2}\right)+3\frac{1}{2}\div\left(-\frac{1}{2}\right)\)
\(=\left(-1,25\right)+\left(-7\right)\)
\(=-8,25\)
Đáp án là: -8.25 nha bạn. Mình thử lại rồi nha. Đúng đó.