Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
1)
a) 315 + ( 125 - x ) = 435
125 - x = 435 - 315
125 - x = 120
x = 125 - 120
x = 5
b) ( x - 105 ) : 2 = 15
x - 105 = 15 . 2
x - 105 = 30
x = 30 + 105
x = 135
c) ( x : 23 + 45 ) . 67 = 8911
x : 23 + 45 = 8911 : 67
x : 23 + 45 = 133
x : 23 = 133 - 45
x : 23 = 88
x = 88 . 23
x = 2024
d) 5 . x - 20 = 3 . ( x - 2 )
x = 7 ( Mình không biết cách trình bày nhưng mình biết kết quả )
2)
a) 2783 + 461 + 217 - 61 = ( 2783 + 217 ) + ( 461 - 61 )
= 3000 + 400 = 3400
b) 123 . 456456 - 456 . 123123 = 0
Ta có : \(\left(\frac{2}{11.13}+\frac{2}{13.15}+...+\frac{2}{19.21}\right)642-\left[0,04:\left(x+1,05\right)\right]:0,12=19\)
=> \(\left(\frac{1}{11}-\frac{1}{13}+\frac{1}{13}-\frac{1}{15}+...+\frac{1}{19}-\frac{1}{21}\right)642-0,04:\left(x+1,05\right):0,12=19\)
=>
(nãy bấm nhầm) tiếp nà :
=> \(\left(\frac{1}{11}-\frac{1}{21}\right)462-0,04:\left(x+1,05\right):0,12=19\)
=> \(\frac{10}{231}.462-0,04:\left(x+1,05\right):0,12=19\)
=> \(20-0,04:\left(x+1,05\right):0,12=19\)
=> 0,04 : (x + 1,05) : 0,12 = 1
=> 0,04 : (x + 1,05) = 0,12
=> \(x+1,05=\frac{1}{3}\)
=> \(x=\frac{1}{3}-1,05=...\)
\(1+\frac{1}{2}\left(1+2\right)+\frac{1}{3}\left(1+2+3\right)+...+\frac{1}{20}\left(1+2+3+...+20\right)=1+\frac{1}{2}.\frac{2.3}{2}+\frac{1}{3}.\frac{3.4}{2}+...+\frac{1}{20}.\frac{20.21}{2}=1+\frac{3}{2}+\frac{4}{2}+...+\frac{21}{2}=1+\frac{24.19}{2}=229\)
sua lai
A) \(\left(44.52.60\right):\left(11.13.15\right)\)
\(=\left(4.11.4.13.4.15\right):\left(11.13.15\right)\)
\(=4^3\left(11.13.15\right):\left(11.13.15\right)\)
\(=64\)
B) \(123.456456-456.123123\)
\(=123.456.1001-456.123.1001\)
\(=56088.1001-56088.1001\)
\(=1001.\left(56088-56088\right)\)
\(=1001.0\)
\(=0\)
C) \(\left(98.7676-9898.76\right):\left(2001.2002....2020\right)\)
\(=\left(98.76.101-98.101.76\right):\left(2001.2002....2020\right)\)
\(=0:\left(2001.2002....2020\right)\)
\(=0\)
A) \(\left(44.52.60\right):\left(11.13.15\right)\)
\(=\left(4.11.4.13.4.15\right):\left(11.13.15\right)\)
\(=4\left(11.13.15\right):\left(11.13.15\right)\)
\(=4.1\)
\(=4\)