tìm x a)(3x-1)^10 =(3x-1)^20
Tìm x :
a. 10 x X - 1 - 3 - 5 - 7 - .... - 19 = 2 + 4 + 6 + .... + 20 .
b. 3x / 2 + 3x / 6 + 3x / 12 + 3x / 20 + 3x / 30 = 10
a ) 10 x X - 1 - 3 - 5 - 7 - ... - 19 = 2 + 4 + 6 + ... + 20
10 x X - 1 - 3 - 5 - 7 - ... - 19 = 110
10 x X - ( 1 + 3 + 5 + 7 + ... + 19 ) = 110
10 x X - 100 = 110
10 x X = 110 + 100
10 x X = 210
X = 210 : 10
X = 21
a 10 x X-1-3-5-7-....-19 = 2+4+6+....+20
10xX-1-3-5-7-....-19=110
10xX=110+1+3+5+7+....+19
10xX=210
X=210:10
X=21
b là 4
tìm x:
a) 2016^x=1
b) x^2=x^5
c) (3x-1)^10=(3x-1)^20
\(2016^x=1\)
\(\Rightarrow x=0\)
tíc mình nha
Tìm x
a) (x-1)^10 = (x-1)^20
b) (3x+1)^2n+1 = 5^2n+1
\(\left(a-1\right)^{10}=\left(a-1\right)^{20}\)
\(\Rightarrow\left(a-1\right)^{20}-\left(a-1\right)^{10}=0\)
\(\Rightarrow\left(a-1\right)^{10}\cdot\left[\left(a-1\right)^{10}-1\right]=0\)
\(\Rightarrow\hept{\begin{cases}\left(a-1\right)^{10}=0\\\left(a-1\right)^{10}-1=0\end{cases}}\)
\(\Rightarrow\hept{\begin{cases}a-1=0\\\left(a-1\right)^{10}=1\end{cases}}\)
\(\Rightarrow\hept{\begin{cases}a=1\\a-1=1\end{cases}}\)
\(\Rightarrow\hept{\begin{cases}a=1\\a=2\end{cases}}\)
a) Ta có:x-1=x-1
=>để \(\left(x-1\right)^{10}=\left(x-1\right)^{20}\)
thì x=1 hoặc x=2
vậy......
hc tốt
Tìm x,biết: a)(x-2,5)^4=(x-2,5)^2
b)(3x-1)^10=(3x-1)^20
c)x^8/243=27
d)32^x.16^x=1024
a) (3x-2)(3x+2)-(3x+4)²=20 b) 6x²-2x(3x+1)=10 c) x²+4x+3=0
a) \(\left(3x-2\right)\left(3x+2\right)-\left(3x+4\right)^2=20\\ \Rightarrow9x^2-4-9x^2-24x-16-20=0\\ \Rightarrow-24x-40=0\\ \Rightarrow-24x=40\\ \Rightarrow x=-\dfrac{5}{3}\)
b) \(6x^2-2x\left(3x+1\right)=10\\ \Rightarrow6x^2-6x^2-2x=10\\ \Rightarrow-2x=10\\ \Rightarrow x=-5\)
c) \(x^2+4x+3=0\\ \Rightarrow\left(x+1\right)\left(x+3\right)=0\\ \Rightarrow\left[{}\begin{matrix}x+1=0\\x+3=0\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=-1\\x=-3\end{matrix}\right.\)
Tính giá trị của biểu thức B = (x + 3)(x + 2) – x(x – 5) - 6 với x = 2.
A. 5. B. 10. C. 15. D. 20.
Tìm x, biết 3x(x + 1) – x(3x – 2) = 10
A. x = 1. B. x = -1. C. x = 2. D. x = -2.
Tìm x
a) 3x - 10 = 2x + 13
b) x + 12 = -5 - x
c) x + 5 - 10 - x
d) 6x + 2 ^ 3 = 2x - 12
e) 12 - x = x + 1
f) 14 - 4x = 3x + 20
a) 3x - 10 = 2x + 13
<=> 3x - 2x = 13+10
<=> x = 23
Vậy x = 23
b) x + 12 = -5 - x
<=> x + x = -5 - 12
<=> 2x = -17
<=> x = -17 : 2
<=> x = -8,5
Vậy x = -8,5
c) x + 5 = 10 - x
<=> x + x = 10 - 5
<=> 2x = 5
<=> x = 5 : 2
<=> x = 2,5
Vậy x = 2,5
d) 6x + 2 ^ 3 = 2x - 12
<=> 6x + 8 = 2x - 12
<=> 6x - 2x = -12 - 8
<=> 4x = -20
<=> x = -20 : 4
<=> x = -5
Vậy x = -5
e) 12 - x = x + 1
<=> -x - x = 1 - 12
<=> -2x = -11
<=> x = -11 : (-2)
<=> x = 5,5
Vậy x= 5,5
f) 14 - 4x = 3x + 20
<=> -4x - 3x = 20 - 14
<=> -7x = 6
<=> x = 6 : (-7)
<=> x = \(-\frac{6}{7}\)
tìm x thuộc z:
a 5x(1/4-1/5-1/10) bé hơn hoặc = x/20 < hoặ = -3x(1/2-1/4-1/5)Sửa đề lại :
Tìm x thuộc Z
\(5\times\left[\frac{1}{4}-\frac{1}{5}-\frac{1}{10}\right]\le\frac{x}{20}\le-3\times\left[\frac{1}{2}-\frac{1}{4}-\frac{1}{5}\right]\)
\(\Leftrightarrow5\times\left[\frac{5}{20}-\frac{4}{20}-\frac{2}{20}\right]\le\frac{x}{20}\le-3\times\left[\frac{10}{20}-\frac{5}{20}-\frac{4}{20}\right]\)
\(\Leftrightarrow5\times\frac{-1}{20}\le\frac{x}{20}\le-3\times\frac{1}{20}\)
\(\Leftrightarrow\frac{-5}{20}\le\frac{x}{20}\le\frac{-3}{20}\)
\(\Leftrightarrow-5\le x\le-3\)
\(\Leftrightarrow x\in\left\{-5;-4;-3\right\}\)
Study well >_<
bn lm câu nafycho mk luôn
(3/5--4/5)x60<x<3/7x(5/6-2+7/2)
1 tìm x . / 12 - 3x / -20 = 10
2 tìm STN x,y sao cho : ( x + 1 ) nhân ( y - 2 ) = 13
1. Ta có: \(\left|12-3x\right|-20=10\)
\(\Rightarrow\left|12-3x\right|=30\)
\(\Rightarrow12-3x=\pm30\)
Nếu \(12-3x=30\Rightarrow3x=-18\Rightarrow x=-6\)
Nếu \(12-3x=-30\Rightarrow3x=42\Rightarrow x=14\)
2. Ta có: \(\left(x+1\right)\left(y-2\right)=13=1.13=13.1=\left(-13\right).\left(-1\right)=\left(-1\right)\left(-13\right)\)
x+1 | 1 | 13 | -13 | -1 |
x | 0 | 12 | -14 | -2 |
y-2 | 13 | 1 | -1 | -13 |
y | 15 | 3 | 1 | -11 |