c ) 86 . 47 - 86 . 17 + 30 . 14

= 86 . ( 47 - 17 ) + 30 . 14

= 86 . 30 + 30 . 14

= 30 . ( 86 + 14 ) 

= 30 . 100

= 3000

a/ \(\left(-27\right)+|-227|+\left(-84\right).\)

\(=\left(-27\right)+227+\left(-84\right)\)

\(=200+\left(-84\right)=116\)

b/ \(=2017+\left(729+\left(-1008\right)\right)\)

\(=2017+\left(-279\right)=1738\)

c/ \(=86.\left(47-17\right)+30.14\)

\(=80.30+30.14\)

\(=30.\left(80+14\right)\)

\(=30.94=2820\)

Nhớ k cho mình nhé! Thank you!!!

a ) ( - 27 ) + I - 227 l + ( - 84 )

= ( - 27 ) + 227 + ( - 84 )

= 200 + ( - 84 )

= 116

ghi ra giấy giú mình nhé . Thank you mọi người

a, 2217

b, 8000

c, -11777.88764

d, \(-\dfrac{7}{26}\)

Bài 1:

\(a,=\left(156+44\right)+2017=200+2017=2217\\ b,=86\left(124-24\right)-600=86\cdot100-600=8000\\ d,=700:\left[25\left(394-498\right)\right]=700:\left[25\cdot\left(-104\right)\right]=700:\left(-2600\right)=-\dfrac{7}{26}\)

Bài 2:

\(a,\Rightarrow x=164+14=178\\ b,\Rightarrow5\left(75-x\right)=225\\ \Rightarrow75-x=45\\ \Rightarrow x=30\\ c,\Rightarrow2x-7=5\Rightarrow x=6\)

a: 86+357+14

=100+357

=457

b: \(3\cdot52-16:22\)

\(=156-\dfrac{8}{11}=\dfrac{1708}{11}\)

+84.000 đồng nha bạn

là 2 000 đồng

\(\dfrac{a+3}{5}=\dfrac{b-2}{3}=\dfrac{c-1}{7}\)

\(\Leftrightarrow\dfrac{3a+9}{15}=\dfrac{5b-10}{15}=\dfrac{7c-7}{49}\)

Theo tính chất dãy tỉ số bằng nhau, ta có:

\(\dfrac{3a+9}{15}=\dfrac{5b-10}{15}=\dfrac{7c-7}{49}=\dfrac{3a+9-\left(5b-10\right)+\left(7c-7\right)}{15-15+49}=\dfrac{\left(3a-5b+7c\right)+9+10-7}{49}=\dfrac{86+12}{49}=\dfrac{98}{49}=2\)

\(\Rightarrow\left\{{}\begin{matrix}3a+9=30\\5b-10=30\\7c-7=98\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}3a=21\\5b=40\\7c=105\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}a=7\\b=8\\c=15\end{matrix}\right.\)

Vì khi chuyển từ can A sang can B 4 lít thì 2 can bằng nhau nên can A nhiều hơn can B 8 lít.
Số lít đầu can A có là:
(86 + 8) : 2 = 47 (lít dầu)