a) \(\left(7+3\dfrac{1}{4}-\dfrac{2}{5}\right)-\left(\dfrac{1}{4}+\dfrac{3}{5}\right)-1\)
\(=\left(7+\dfrac{13}{4}-\dfrac{2}{5}\right)-\left(\dfrac{1}{4}+\dfrac{3}{5}\right)-1\)
\(=7+\dfrac{13}{4}-\dfrac{2}{5}-\dfrac{1}{4}-\dfrac{3}{5}-1\)
\(=\left(\dfrac{13}{4}-\dfrac{1}{4}\right)+\left(-\dfrac{2}{5}-\dfrac{3}{5}\right)+\left(7-1\right)\)
\(=\dfrac{12}{4}+\dfrac{-5}{5}+6\)
\(=3-1+6=8\)
b) \(\dfrac{1}{5}\cdot\left(-24,8\right)+\dfrac{1}{5}\cdot4,8\)
\(=\dfrac{1}{5}\cdot\left(-24,8+4,8\right)\)
\(=\dfrac{1}{5}\cdot\left(-20\right)\)
\(=\dfrac{-20}{5}\)
\(=-4\)
`a, ( 7 + 3 1/4 - 2/5) - (1/4 + 3/5)-1`
`= ( 7 + 13/4 - 2/5 ) -(1/4 + 3/5)-1`
`= 7 + 13/4 - 2/5 - 1/4 - 3/5 -1`
`= ( 7-1) +(13/4 -1/4) +(-2/5 -3/5)`
`= 6 + 12/4 + (-5/5)`
`= 6 + 3 + (-1)`
`= 8`
`b, 1/5 . ( -24,8) + 1/5 . 4,8`
`= 1/5 . (-24,8 + 4,8)`
`= 1/5 . (-20)`
`= -20/5`
`=-4`
giải hộ bài 5 có hình + cách giải với ạ
