Tìm x:
2 ^ x + 1 - 2= 14
Tìm x, biết: x + 2/7=1/2
A.x= 3/14 B. x=2/14 C. x=13/3 D. x=1/5.
X+\(\dfrac{2}{7}\)=\(\dfrac{1}{2}\)
X = \(\dfrac{1}{2}\)-\(\dfrac{2}{7}\)
X = \(\dfrac{3}{14}\)
Chọn đáp án A. \(\dfrac{3}{14}\)
tìm số nguyên x
1) x+(x+1)+(x+2)+(x+3)+...+13+14=14
2) 25+24+23+...+x+(x-1)+(x-2)=25
\(x+\left(x+1\right)+\left(x+2\right)+....+13+14=14\Leftrightarrow x+\left(x+1\right)+....+13\Leftrightarrow x=-13\)
\(25+24+23+....+x+\left(x-1\right)+\left(x-2\right)=25\Leftrightarrow24+....+\left(x-2\right)=0\Leftrightarrow x-2=-24\)
\(\Leftrightarrow x=-22\)
bạn làm rõ hơn đi
1. Tìm x : 1/2 + 1/14 + 1/35 +....+ 1/x(x+3):2 = 9/14
Mong các bạn giúp mình !
Ta có : \(\frac{1}{2}+\frac{1}{14}+\frac{1}{35}+...+\frac{1}{x\left(x+3\right):2}=\frac{9}{14}\)
\(\Rightarrow2\left(\frac{1}{4}+\frac{1}{28}+\frac{1}{70}+...+\frac{1}{x\left(x+3\right)}\right)=\frac{9}{14}\)
\(\Rightarrow2.\frac{1}{3}\left(\frac{3}{1.4}+\frac{3}{4.7}+\frac{3}{7.10}+...+\frac{3}{x\left(x+3\right)}\right)=\frac{9}{14}\)
\(\Rightarrow\frac{2}{3}\left(1-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{10}+...+\frac{1}{x}-\frac{1}{x+3}\right)=\frac{9}{14}\)
\(\Rightarrow1-\frac{1}{x+3}=\frac{27}{28}\)
\(\Rightarrow\frac{1}{x+3}=\frac{1}{28}\)
=> x + 3 = 28
=> x = 25
Tìm X
x+(x+1)+(x+2)+............+13+14=14
Tìm x, biết ( 1 4 ) x = 16
A. x = -2 B. x = 2
C. x = 1/2 D. x = -1/2
Tìm x: Cần gấp ạ
1, -15 + x= - 14 - (-57) 2,(-14) + x - 7 = -10 3, -x - 14 + 32 = -26 4, x-(-19) - (-11) = 0
1, -15 + \(x\) = -14 - (-57)
-15 + \(x\) = -14 + 57
\(x\) = -14 + 57 + 15
\(x\) = 43 + 15
\(x\) = 58
2, (-14) + \(x\) - 7 = -10
-14 + \(x\) - 7 = -10
- 21 + \(x\) = - 10
\(x\) = -10 + 21
\(x\) = 11
3, - \(x\) - 14 + 32 = -26
- \(x\) + 18 = - 26
\(x\) = 18 + 26
\(x\) = 44
Tìm x
2^x + 2^x-1 + 2^x-2 = 14
Tìm x biết
(x+2)^2-(x+1)(x-1)=9
x(2x+7)+4x+14=0
(x+1)^3-x^2(x+3)=2
1) \(\Rightarrow x^2+4x+4-x^2+1=9\)
\(\Rightarrow4x=4\Rightarrow x=1\)
2) \(\Rightarrow x\left(2x+7\right)+2\left(2x+7\right)=0\)
\(\Rightarrow\left(2x+7\right)\left(x+2\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=-\dfrac{7}{2}\\x=-2\end{matrix}\right.\)
3) \(\Rightarrow x^3+3x^2+3x+1-x^3-3x^2=2\)
\(\Rightarrow3x=1\Rightarrow x=\dfrac{1}{3}\)
Tìm số nguyên x:
x+(x+1)+(x+2)+(x+3)+....+(x+13)+(x+14)=14
\(x+\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+...+\left(x+14\right)=14\)
\(x+x+1+x+2+x+3+...+x+14=14\)
\(15x+\left(1+2+3+...+14\right)=14\)
\(15x+\frac{\left(14+1\right).14}{2}=14\)
\(15x+105=14\)
\(15x=-91\)
\(x=-\frac{91}{15}=-6,06\)
Ko chắc lắm
x+(x+1)+(x+2)+(x+3)+...+(x+13)+(x+14)=14
x+x+1+x+2+x+3+...+x+13+x+14=14
(x+x+x+x+...+x+x)+(1+2+3+...+14)=14
15x + 14 = 14
15x = 14 - 14
15x = 0
x = 0:15
x = 0
Vậy x=0
Hoàng hôn ( Cool Team ) bạn thông minh quá (1+2+3+4+...+14)=14