Tìm x biết [|3x+1|-11]=3
K
Khách
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Những câu hỏi liên quan
PT
4
H
22 tháng 12 2022
`x . 3/7 = 2/3`
`=>x= 2/3 : 3/7`
`=>x= 2/3 . 7/3`
`=>x=14/9`
`-----------`
`x : 8/11 = 11/3`
`=>x= 11/3 . 8/11`
`=>x= 88/33`
`=>x=8/3`
`-----------`
`4/7 . x - 2/3 = 1/5`
`=> 4/7 . x = 1/5 +2/3`
`=>4/7 . x =3/15 + 10/15`
`=>4/7 . x =13/15`
`=>x= 13/15 : 4/7`
`=>x= 13/15 xx 7/4`
`=>x= 91/60`
AH
Akai Haruma
Giáo viên
22 tháng 12 2022
Lời giải:
$x.\frac{3}{7}=\frac{2}{3}$
$x=\frac{2}{3}: \frac{3}{7}=\frac{14}{9}$
-----------
$x: \frac{8}{11}=\frac{11}{3}$
$x=\frac{11}{3}.\frac{8}{11}=\frac{8}{3}$
-----------
$\frac{4}{7}x-\frac{2}{3}=\frac{1}{5}$
$\frac{4}{7}x=\frac{2}{3}+\frac{1}{5}=\frac{13}{15}$
$x=\frac{13}{15}: \frac{4}{7}=\frac{91}{60}$
CM
4 tháng 4 2019
Ta có
( 3 x – 1 ) 2 + 2 ( x + 3 ) 2 + 11 ( 1 + x ) ( 1 – x ) = 6 ⇔ ( 3 x ) 2 – 2 . 3 x . 1 + 1 2 + 2 ( x 2 + 6 x + 9 ) + 11 ( 1 – x 2 ) = 6 ⇔ 9 x 2 – 6 x + 1 + 2 x 2 + 12 x + 18 + 11 – 11 x 2 = 6 ⇔ ( 9 x 2 + 2 x 2 – 11 x 2 ) + ( - 6 x + 12 x ) = 6 – 1 – 11 – 18
ó 6x = -24 ó x = -4
Vậy x = -4
Đáp án cần chọn là: A
NH
1
ND
Nguyễn Đức Trí
VIP
29 tháng 8 2023
1) \(\left|x\right|< 10\)
\(\Leftrightarrow-10< x< 10\)
2) \(\left|x\right|>11\)
\(\Leftrightarrow\left[{}\begin{matrix}x< -11\\x>11\end{matrix}\right.\)
3) \(\left|x\right|\ge2x\left(\forall x\ge0\right)\)
\(\)\(\Leftrightarrow\left[{}\begin{matrix}x\le-2x\\x\ge2x\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}3x\le0\\x\le0\end{matrix}\right.\)
\(\Leftrightarrow x=0\) \(\left(thỏa.đk:x\ge0\right)\)
4) \(\left|x\right|\le-3x\left(\forall x\le0\right)\)
\(\Leftrightarrow\left\{{}\begin{matrix}x\ge-\left(-3x\right)\\x\le-3x\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}2x\le0\\4x\le0\end{matrix}\right.\)
\(\Leftrightarrow x\le0\) \(\left(thỏa.đk\right)\)
20 tháng 9 2021
\(1,\\ \left(x-7\right)^{x+1}-\left(x-7\right)^{x+11}=0\\ \Leftrightarrow\left(x-7\right)^{x+1}\left[1-\left(x-7\right)^{10}\right]=0\\ \Leftrightarrow\left[{}\begin{matrix}\left(x-7\right)^{x+1}=0\\\left(x-7\right)^{10}=1\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x-7=0\\x-7=1\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=7\\x=8\end{matrix}\right.\)
\(2,\\ a,\left|2x-3\right|>5\Leftrightarrow\left[{}\begin{matrix}2x-3< -5\\2x-3>5\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x< -1\\x>4\end{matrix}\right.\\ b,\left|3x-1\right|\le7\Leftrightarrow\left[{}\begin{matrix}3x-1\le7\\1-3x\le7\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x\le\dfrac{8}{3}\\x\ge-2\end{matrix}\right.\\ c,\cdot x< -\dfrac{3}{2}\\ \Leftrightarrow5-3x+\left(-2x-3\right)=7\Leftrightarrow2-5x=7\Leftrightarrow x=-1\left(ktm\right)\\ \cdot-\dfrac{3}{2}\le x\le\dfrac{5}{3}\\ \Leftrightarrow\left(5-3x\right)+\left(2x+3\right)=7\Leftrightarrow8-x=7\Leftrightarrow x=1\left(tm\right)\\ \cdot x>\dfrac{5}{3}\\ \Leftrightarrow\left(3x-5\right)+\left(2x+3\right)=7\Leftrightarrow5x-2=7\Leftrightarrow x=\dfrac{9}{5}\left(tm\right)\\ \Leftrightarrow S=\left\{1;\dfrac{9}{5}\right\}\)
H9
HT.Phong (9A5)
CTVHS
8 tháng 10 2023
a) \(\left(x+3\right)\left(x+1\right)-x\left(x-5\right)=11\)
\(\Leftrightarrow x^2+x+3x+3-x^2+5x=11\)
\(\Leftrightarrow9x+3=11\)
\(\Leftrightarrow9x=11-3\)
\(\Leftrightarrow9x=8\)
\(\Leftrightarrow x=\dfrac{8}{9}\)
b) \(\left(8x+2\right)\left(1-3x\right)+\left(6x-1\right)\left(4x-10\right)=-50\)
\(\Leftrightarrow\left(8x-24x^2+2-6x\right)+\left(24x^2-60x-4x+10\right)=-50\)
\(\Leftrightarrow2x-24x^2+2+24x^2-64x+10=-50\)
\(\Leftrightarrow-62x+12=-50\)
\(\Leftrightarrow-62x=-50-12\)
\(\Leftrightarrow-62x=-62\)
\(\Leftrightarrow x=\dfrac{-62}{-62}\)
\(\Leftrightarrow x=1\)
ND
Nguyễn Đăng Nhân
CTVHS
8 tháng 10 2023
a) \(\left(x+3\right)\left(x+1\right)-x\left(x-5\right)=11\)
\(x^2+x+3x+3-x^2+5x=11\)
\(x+8x+3=11\)
\(x+8x=8\)
\(x\left(8+1\right)=8\)
\(x=\dfrac{8}{9}\)
b) \(\left(8x+2\right)\left(1-3x\right)+\left(6x-1\right)\left(4x-10\right)=-50\)
\(8x-24x^2+2-6x+24x^2-60x-4x+10=-50\)
\(-62x+12=-50\)
\(-62x=-62\)
\(x=1\)
6 tháng 11 2023
a: 18:(x-3)=6
=>x-3=18:6=3
=>x=3+3=6
b: \(3^{x-1}+4=85\)
=>\(3^{x-1}=81\)
=>\(3^{x-1}=3^4\)
=>x-1=4
=>x=5
c: 2x+3x=55
=>5x=55
=>x=55/5=11
d: \(\left(x-3\right)^3+11=53\)
=>\(\left(x-3\right)^3=53-11=42\)
=>\(x-3=\sqrt[3]{42}\)
=>\(x=\sqrt[3]{42}+3\)
KV
6 tháng 11 2023
a) 18 : (x - 3) = 6
x - 3 = 18 : 6
x - 3 = 3
x = 3 + 3
x = 6
b) 3ˣ⁻¹ + 4 = 85
3ˣ⁻¹ = 85 - 4
3ˣ⁻¹ = 81
3ˣ⁻¹ = 3⁴
x - 1 = 4
x = 4 + 1
x = 5
c) 2x + 3x = 55
5x = 55
x = 55 : 5
x = 11
d) Sửa đề:
(x - 3)³ - 11 = 53
(x - 3)³ = 53 + 11
(x - 3)³ = 64
(x - 3)³ = 4³
x - 3 = 4
x = 4 + 3
x = 7
\(\left|3x+1\right|-11=3\)
\(\Leftrightarrow\left|3x+1\right|=14\)
\(\Leftrightarrow\orbr{\begin{cases}3x+1=14\\3x+1=-14\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}3x=13\\3x=-15\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{13}{3}\\x=-5\end{cases}}\)
\(\left|3.x+1\right|-11=3\)
\(\left|3.x+1\right|=3+11\)
\(\left|3.x+1\right|=14\)
\(\Rightarrow\orbr{\begin{cases}3.x+1=14\\3.x+1=-14\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}3.x=14-1=13\\3.x=-14-1=-15\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=13:3=\frac{13}{3}\\x=-15:3=-5\end{cases}}\)
Vậy \(x\in\left\{\frac{13}{3};-5\right\}\)