Đại số lớp 6

IT

P = 2/3-1/4+5/11 trên 5/12+1-7/11

NQ
12 tháng 4 2017 lúc 14:56

\(P=\dfrac{\dfrac{2}{3}-\dfrac{1}{4}+\dfrac{5}{11}}{\dfrac{5}{12}+1-\dfrac{7}{11}}=\dfrac{\dfrac{88}{132}-\dfrac{33}{132}+\dfrac{60}{132}}{\dfrac{55}{132}+\dfrac{132}{132}-\dfrac{84}{132}}=\dfrac{\dfrac{88-33+60}{132}}{\dfrac{55+132-84}{132}}=\dfrac{\dfrac{115}{132}}{\dfrac{103}{132}}=\dfrac{115}{132}\cdot\dfrac{132}{103}=\dfrac{115}{103}\)Vậy P=\(\dfrac{115}{103}\).

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H24
12 tháng 4 2017 lúc 14:56

\(P=\dfrac{\dfrac{2}{3}-\dfrac{1}{4}+\dfrac{5}{11}}{\dfrac{5}{12}+1-\dfrac{7}{11}}\)

Cho \(A=\dfrac{2}{3}-\dfrac{1}{4}+\dfrac{5}{11}\)

\(A=\dfrac{5}{12}+\dfrac{5}{11}\)

\(A=\dfrac{115}{132}\)

Cho \(B=\dfrac{5}{12}+1-\dfrac{7}{11}\)

\(B=\dfrac{17}{12}-\dfrac{7}{11}\)

\(B=\dfrac{103}{132}\)

\(P=\dfrac{A}{B}\)

\(\Rightarrow P=\dfrac{115}{132}:\dfrac{103}{132}\)

\(\Rightarrow P=\dfrac{115}{103}\)

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