141:3 = ?
17.3²-x:3²=141
\(17\cdot3^2-x:3^2=141\)
\(153-x:9=141\)
\(x:9=153-141\)
\(x:9=12\)
\(x=12\cdot9=108\)
141 + 130 x 3 = \(\dfrac{x+280}{x}\) + 390
=>280/x+1+390=141+390
=>280/x+391=140+391
=>280/x=140
hay x=2
-1/3 × 141/17 - 39/3 × -1/17
Tính:
\(\dfrac{-1}{3}.\dfrac{141}{17}-\dfrac{39}{3}.\dfrac{-1}{17}\)
Ta có: \(\dfrac{-1}{3}\cdot\dfrac{141}{17}-\dfrac{39}{3}\cdot\dfrac{-1}{17}\)
\(=\dfrac{-1}{3}\cdot\dfrac{141}{17}-\dfrac{-1}{3}\cdot\dfrac{39}{17}\)
\(=\dfrac{-1}{3}\cdot\left(\dfrac{141}{17}-\dfrac{39}{17}\right)\)
\(=\dfrac{-1}{3}\cdot6=-2\)
Câu 1: Thực hiện phép tính
a, \(\dfrac{7}{9}-\dfrac{16}{9}\)
b, \(\dfrac{2}{-15}+\dfrac{7}{10}\)
c, \(\left(4\dfrac{2}{3}-4\dfrac{3}{4}\right):\dfrac{-5}{12}-\dfrac{4}{5}\)
d, \(\dfrac{-141}{157}.\dfrac{23}{59}-\dfrac{141}{157}.\dfrac{36}{59}+\dfrac{16}{-157}\)
a. 7/9 - 16/9 = -9/9 = -1
b. 2/-15 + 7/10 = 17/30
c. (4 2/3 - 4 3/4) : -5/12 - 4/5
= (14/3 - 19/4) : (-5/12) - 4/5
= -1/12 : (-5/12) - 4/5
= 1/5 - 4/5
= -3/5
x/3=y/4 ; y/5=z/6 ; x-2y+3z=141
\(\dfrac{x}{3}=\dfrac{y}{4}\Rightarrow\dfrac{x}{15}=\dfrac{y}{20}\\ \dfrac{y}{5}=\dfrac{z}{6}\Rightarrow\dfrac{y}{20}=\dfrac{z}{24}\\ \Rightarrow\dfrac{x}{15}=\dfrac{y}{20}=\dfrac{z}{24}\)
Áp dụng t/c dtsbn ta có:
\(\dfrac{x}{15}=\dfrac{y}{20}=\dfrac{z}{24}=\dfrac{x-2y+3z}{15-2.20+3.24}=\dfrac{141}{47}=3\)
\(\dfrac{x}{15}=3\Rightarrow x=45\\ \dfrac{y}{20}=3\Rightarrow y=60\\ \dfrac{z}{24}=3\Rightarrow z=72\)
Tìm X, biết 141 : X = 3. Vậy X có giá trị là :
A. 423
B. 144
C. 138
D. 47
Làm tròn số 3, 141 59 đến hàng phần nghìn
TL
3,142
HT
TÌM X :
. -12 . ( x-5) + 7 . ( 3-x) = -141
-12x-(-12.5)+(7.3-7x)=-141
-12x+60+21-7x=-141
(-12x-7x)=-141-60-21
-19x=-222
x=-222:(-19)
x=222/19