Ai giúp mk vớ
Tính nhanh:
a, $\frac{-7}{813}$ + 496 .($\frac{-7}{813}$ )+ ($\frac{-7}{813}$ ).316
b, $\frac{-9}{10}$ . $\frac{5}{14}$ +$\frac{1}{10}$ . ($\frac{-9}{2}$ ) +$\frac{1}{7}$ .($\frac{-9}{10}$ )
c, $\frac{12}{19}$ .$\frac{7}{5}$ .$\frac{-13}{17}$. $\frac{19}{12}$ .$\frac{17}{13}$
d, $\frac{75}{100}$ + 1,1 : ($\frac{2}{5}$ – 1$\frac{1}{2}$) – ( $\frac{1}{3}$ ) ²
Ai giúp mk vớ Tính nhanh: a, $\frac{-7}{813}$ + 496 .($\frac{-7}{813}$ )+ ($\frac{-7}{813}$ ).316 b, $\frac{-9}{10}$ . $\frac{5}{14}$ +$\frac{1}
By Ayla
$a$) `-7/{813} + 496. (-7/{813}) + (-7/{813}) . 316`
`= -7/{813}. (1 + 496 + 316)`
`= -7/{813} . 813`
`= -7`.
$b$) `-9/{10} . 5/{14} + 1/{10} . (-9/2) + 1/7 . (-9/{10})`
`= -9/{10} . 5/{14} + (-9/{10}) . 1/2 + 1/7 . (-9/{10})`
`= -9/{10} . (5/{14} + {7}/{14} + 2/{14})`
`= -9/{10}. 1`
`= -9/{10}`.
$c$) `{12}/{19} . 7/5 . {-13}/{17} . {19}/{12} . {17}/{13}`
`= ({12}/{19} . {19}/{12}) . (-{13}/{17} . {17}/{13}) . 7/5`
`= 1.(-1) . 7/5`
`= -7/5`.
$d$) `{75}/{100} + 1,1 : (2/5 – 1 1/2) – (1/3)^2`
`= 3/4 + {11}/{10} : (2/5 – 3/2) – 1/9`
`= 3/4 + {11}/{10} : {-11}/{10} – 1/9`
`= 3/4 + (-1) – 1/9`
`= -{13}/{36}`.
`a)-7/813 + 496 . (-7/813) + (-7/813) . 316`
`= -7/813 . ( 1 + 496 + 316)`
`= -7/813 . 813`
`= -7`
`b) -9/10 . 5/14 + 1/10 . (-9/2) + 1/7 . (-9/10)`
`= -9/10 . ( 5/14 + 1/7) + 1/10 . (-9/2) `
`= -9/10 . 1/2 + 1/10 . (-9/2)`
`= -9/10 . 1/2 + -9/10 . 1/2`
`=-9/10 . ( 1/2 + 1/2)`
`= -9/10 . 1`
`=-9/10`
`c) 12/19 . 7/5 . -13/17 . 19/12 . 17/13`
`= ( 12/19 . 19/12) . ( -13/17 . 17/13) . 7/5`
`= 1 . (-1) . 7/5`
`= (-1) . 7/5`
`= -7/5`
`d) 75/100 + 1,1 : ( 2/5 – 1 1/2) – (1/3)²`
`= 3/4 + 11/10 : ( 2/5 – 3/2) – 1/9`
`= 3/4 + 11/10 : (-11/10) – 1/9`
`= 3/4 + (-1) – 1/9`
`= 27/36 + (-36/36) – 4/36`
=`\frac{27 + (-36) – 4}{36}`
`= -13/36`