Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(3A=3^2+3^3+...+3^{101}\)
=>\(A=\dfrac{3^{101}-3}{2}\)
`a)25/(x+1)-1 1/6=-1/3-0,5`
`=>25/(x+1)=-1/3-1/2+1+1/6`
`=>25/(x+1)=1/3`
`=>75=x+1`
`=>x=74`
Vậy `x=74`
`b)(2x+25 3/5)^2-9/25=0`
`=>(2x+128/5)=9/25`
`**2x+128/5=3/5`
`=>2x=-125/5=-25`
`=>x=-25/2`
`**2x+128/5=-3/5`
`=>2x=-131/5`
`=>x=-131/10`
a) \(2.\left(x+\frac{2}{5}\right)+1\frac{1}{4}=\frac{11}{20}\)
\(2.\left(x+\frac{2}{5}\right)+\frac{5}{4}=\frac{11}{20}\)
\(2.\left(x+\frac{2}{5}\right)=\frac{-7}{10}\)
\(x+\frac{2}{5}=\frac{-7}{20}\)
\(x=\frac{-13}{20}\)
Vậy \(x=\frac{-13}{20}\)
b)\(x-1\frac{1}{8}-\frac{2}{3}x-\frac{5}{6}x=75\%\)
\(\left(x-\frac{2}{3}x-\frac{5}{6}x\right)-\frac{9}{8}=\frac{3}{4}\)
\(\frac{-1}{2}x-\frac{9}{8}=\frac{3}{4}\)
\(\frac{-1}{2}x=\frac{15}{8}\)
\(x=\frac{-15}{4}\)
Vậy \(x=\frac{-15}{4}\)
a) x - 1/2 = 3/5
x = 3/5 + 1/2
x = 11/10
b) x - 1/2 = -2/3
x = -2/3 + 1/2
x = -1/6
c) 2/5 - x = 0,25
x = 2/5 - 0,25
x = 2/5 - 1/4
x = 3/20
Mình làm câu khó thôi nhé.
2x chia hết cho 3
=>(2x+x-x) chia hết cho 3
=>(3x-x) chia hết cho 3
3x chia hết cho 3=>x chia hết cho 3
=>x thuộc B(3)={0;3;6;...}
Vậy x thuộc {0;3;6;...ư}
\(3\left(x+2\right)^2-5^2=2.5^2\)
\(\Rightarrow3\left(x+2\right)^2=2.5^2+5^2\)
\(\Rightarrow3\left(x+2\right)^2=5^2\left(2+1\right)\)
\(\Rightarrow3\left(x+2\right)^2=5^2.3\)
\(\Rightarrow\left(x+2\right)^2=5^2\)
\(\Rightarrow\left[{}\begin{matrix}x+2=5\\x+2=-5\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=3\\x=-7\end{matrix}\right.\) \(\Rightarrow x=3\left(x\inℕ\right)\)
3(x + 2)² - 5² = 2.5²
3(x + 2)² - 25 = 50
3(x + 2)² = 50 + 25
3(x + 2)² = 75
(x + 2)² = 75 : 3
(x + 2)² = 25
x + 2 = 5 hoặc x + 2 = -5
*) x + 2 = 5
x = 5 - 2
x = 3 (nhận)
*) x + 2 = -5
x = -5 - 2
x = -7 (loại)
Vậy x = 3
a, 7x + 10x = 5x
17x = 5x
17x - 5x = 0
12x = 0
x =0
2;
a, 4x + 7x = 22
11x = 22
x = 2
b, 12x - 8x = 25
4x = 25
x = \(\dfrac{25}{4}\)
c, \(\dfrac{1}{2}\)x - \(\dfrac{1}{3}\)x = \(\dfrac{4}{5}\)
(\(\dfrac{1}{2}-\dfrac{1}{3}\))x = \(\dfrac{4}{5}\)
\(\dfrac{1}{6}\)x = \(\dfrac{4}{5}\)
x = \(\dfrac{4}{5}\) : \(\dfrac{1}{6}\)
x = \(\dfrac{24}{5}\)
a) 9x-1=32
( 32 )x-1 = 32
32x-2 = 32
⇒ 2x-2 = 2
2x = 2+2
2x = 4
x = 4 : 2
x = 2
b) 5x+2=625
5x+2= 54
⇒ x+2 = 4
x = 4-2
x = 2
c) 2x: 25= 2
2x:25 = 21
2x = 21 . 25
2x = 26
⇒ x = 6
d) 3x:27=3
3x:33 = 31
3x = 31.33
3x = 34
⇒ x = 4
a) Ta có: \(9^{x-1}=3^2\)
\(\Leftrightarrow3^{2x-2}=3^2\)
\(\Leftrightarrow2x-2=2\)
\(\Leftrightarrow2x=4\)
hay x=2
Vậy: x=2
b) Ta có: \(5^{x+2}=625\)
\(\Leftrightarrow5^{x+2}=5^4\)
\(\Leftrightarrow x+2=4\)
hay x=2
Vậy: x=2
c) Ta có: \(2^x:2^5=2\)
\(\Leftrightarrow2^{x-5}=2^1\)
\(\Leftrightarrow x-5=1\)
hay x=6
Vậy: x=6
d) Ta có: \(3^x:27=3\)
\(\Leftrightarrow3^x:3^3=3\)
\(\Leftrightarrow3^{x-3}=3^1\)
\(\Leftrightarrow x-3=1\)
hay x=4
Vậy: x=4
Bạn xem lại đề
\(53.x+2-25=3100\)
\(53.x+2=3100+25\)
\(53.x+2=3125\)
\(53.x=3125-2\)
\(53.x=3123\)
\(x=3123:53\)
\(x=\dfrac{3123}{53}\)