Bài 60 trang 33 SGK Toán 6 tập 2

Đề bài

Tìm x, biết:

a) \(x - \dfrac{3}{4}=\dfrac{1}{2}\) ;                              

b) \(\dfrac{-5}{6}-x=\dfrac{7}{12}+\dfrac{-1}{3}\) ;

Lời giải chi tiết

a)

\(x - \dfrac{3}{4}=\dfrac{1}{2}\)

\(x= \dfrac{1}{2}+\dfrac{3}{4}\)

\(x= \dfrac{2+3}{4}\)

\(x=\dfrac{5}{4}\)                     

b) 

\(\dfrac{-5}{6}-x=\dfrac{7}{12}+\dfrac{-1}{3}\)

\(\dfrac{-5}{6}-x=\dfrac{7}{12}+\dfrac{-4}{12}\)

\(\dfrac{-5}{6}-x=\dfrac{7+(-4)}{12}\) 

\(\dfrac{-5}{6}-x=\dfrac{3}{12}\).

\(x=\dfrac{-5}{6}-\dfrac{3}{12}\)

\(x=\dfrac{-10}{12}+\dfrac{-3}{12}\)

\(x=\dfrac{(-10)+(-3)}{12}\)

\(x=\dfrac{-13}{12}.\)

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