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\(a\text{)}1,\left(7\right)=1+0,\left(7\right)=1+\frac{7}{9}=\frac{16}{9}\)
\(b\text{)}0,\left(45\right)=\frac{45}{99}\)
\(c\text{)}0,0\left(31\right)=0,\left(31\right):10=\frac{31}{99}:10=\frac{31}{990}\)
\(d\text{)}1,8\left(33\right)=1,8+0,0\left(33\right)=1,8+0,\left(33\right):10=1,8+\frac{33}{990}=\frac{54}{30}+\frac{1}{30}=\frac{55}{30}\)
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Ta có: \(\widehat{B_1}+\widehat{B_2}=180^o\)(hai góc kề bù)
suy ra \(\widehat{B_2}+\frac{1}{2}\widehat{B_2}=\frac{3}{2}\widehat{B_2}=180^o\Leftrightarrow\widehat{B_2}=120^o\)
\(\widehat{B_1}=\frac{1}{2}\widehat{B_2}=120^o\div2=60^o\)
Có \(a//b\)nên \(\widehat{B_1}=\widehat{A_1}\)(hai góc so le trong)
suy ra \(\widehat{A_1}=60^o\)
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máy tính xin hân hạnh đồng hành cùng với lê Kiều Trinh
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a: \(-\dfrac{4}{7}-\dfrac{5}{13}\cdot\dfrac{-39}{25}+\dfrac{-1}{42}:\dfrac{-5}{6}\)
\(=\dfrac{-4}{7}+\dfrac{3}{5}+\dfrac{1}{35}\)
\(=\dfrac{-20}{35}+\dfrac{21}{35}+\dfrac{1}{35}\)
\(=\dfrac{2}{35}\)
a) 23,4(5) + 45,(5) = 2111/90 + 410/9 = 2111/90 + 4100/90 = 6211/90
b) 0,0(2) - 0,(1) = 1/45 - 1/9 = 1/45 - 5/45 = -4/45