tính nhanh: 44.3 x 8.6 + 17.2 x 42.7 - 4.3 x2 x 29.7
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a) \(97\cdot13+130\cdot0,3\)
\(=97\cdot13+13\cdot3\)
\(=13\cdot\left(97+3\right)\)
\(=13\cdot100\)
\(=1300\)
b) \(86\cdot153-530\cdot8,6\)
\(=86\cdot153-53\cdot86\)
\(=86\cdot\left(153-53\right)\)
\(=86\cdot100\)
\(=8600\)
a) \(97.13+130.0,3\)
\(=97.13+13.3\)
\(=13\left(97+3\right)=13.100=1300\)
b) \(86.153-530.8,6\)
\(=86.153-53.86\)
\(=86.\left(153-53\right)=86.100=8600\)
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Bài 1:
a: Ta có: \(48751-\left(10425+y\right)=3828:12\)
\(\Leftrightarrow y+10425=48751-319=48432\)
hay y=38007
b: Ta có: \(\left(2367-y\right)-\left(2^{10}-7\right)=15^2-20\)
\(\Leftrightarrow2367-y=1222\)
hay y=1145
Bài 2:
Ta có: \(8\cdot6+288:\left(x-3\right)^2=50\)
\(\Leftrightarrow288:\left(x-3\right)^2=2\)
\(\Leftrightarrow\left(x-3\right)^2=144\)
\(\Leftrightarrow\left[{}\begin{matrix}x-3=12\\x-3=-12\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=15\\x=-9\end{matrix}\right.\)