Bài 71: trang 37 sgk Toán 6 tập 2
Tìm x, biết:
a) \(x-\frac{1}{4}=\frac{5}{8}.\frac{2}{3}\)
b) \(\frac{x}{126}=\frac{-5}{9}.\frac{4}{7}\)
Bài Làm:
a) \(x - {1 \over 4} = {5 \over 8}.{2 \over 3} \)
\(x - {1 \over 4} = {5 \over {12}} \)
\(x\,\,\,\,\,\,\,\,\,\, = {5 \over {12}} + {1 \over 4} \)
\(x\,\,\,\,\,\,\,\,\,\, = {8 \over {12}} = {2 \over 3}\)
b) \({x \over {126}} = {{ - 5} \over 9}.{4 \over 7} \)
\({x \over {126}} = {{ - 20} \over {63}} \)
\(63.x = - 20.126 \)
\(x = {{ - 20.126} \over {63}} \)
\(x = - 40\)