\(2^x+2^{x+1}+2^{x+2}+2^{x+3}+...+2^{x+2021}=2^{2025}+8\)
Tìm x,biết:\(2^x+2^{x+1}+2^{x+2}+2^{x+3}+...+2^{x+2021}=2^{2025}+8\)
Tìm giá trị nhỏ nhất
A)x^2+4y^2-2x-14y+2025 B)(x-1) .(x+2).(x+3).(x+6)-2047. C)x^2-4x+2021. D)x^2 +y^2+xy-2x-4y+2014
Tính : ( 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 +...........................+ 2016 + 2025 ) x ( 12,1 x 2 - 24,2 x 1 ) =............
(1+2+3+4+5+6+7+8+9+...............................+2016+2025) x (24,2 - 24,2) = (1 + 2 +3+4+5+6+7+8+9+...............................+2016+2025) x 0 = 0
Tìm số nguyên dương x sao cho 5x +13 là bội của 2x+1
Tìm x biết (2x-18).(3x+12)=0
Tính S= 1-2-3+4+
5-6-7+8+...+2021-2022-2023+2024+2025
1. Giải:
Do \(5x+13B\in\left(2x+1\right)\Rightarrow5x+13⋮2x+1.\)
\(\Rightarrow2\left(5x+13\right)⋮2x+1\Rightarrow10x+26⋮2x+1.\)
\(\Rightarrow5\left(2x+1\right)+21⋮2x+1.\)
Do 5(2x+1)⋮2x+1⇒ Ta cần 21⋮2x+1.
⇒ 2x+1 ϵ B(21)=\(\left\{1;3;7;21\right\}.\)
Ta có bảng:
2x+1 | 1 | 3 | 7 | 21 |
x | 0 | 1 | 3 | 10 |
TM | TM | TM | TM |
Vậy xϵ\(\left\{0;1;3;10\right\}.\)
2. Giải:
Do (2x-18).(3x+12)=0.
⇒ 2x-18=0 hoặc 3x+12=0.
⇒ 2x =18 3x =-12.
⇒ x =9 x =-4.
Vậy xϵ\(\left\{-4;9\right\}.\)
3. S= 1-2-3+4+5-6-7+8+...+2021-2022-2023+2024+2025.
S= (1-2-3+4)+(5-6-7+8)+...+(2021-2022-2023+2024)+2025 Có 506 cặp.
S= 0 + 0 + ... + 0 + 2025.
⇒S= 2025.
Bài 3 :
a) Tìm x biết: (x+2)2 +(x+8)(x+2)
b) Tính giá trị biểu thức : B= (x+y)(x2 – xy + y2) –y3, tại x =10, y = 2021
Bài 3 :
a) Tìm x biết: (x+2)2 +(x+8)(x+2)
b) Tính giá trị biểu thức : B= (x+y)(x2 – xy + y2) –y3, tại x =10, y = 2021
Tìm x,y biết
a,\(\left(2^3\right)^{1^{2005}}\cdot x+2005^0\cdot x=994-15:3+1^{2025}\)
b,\(2^x+2^{x+1}+2^{x+2}+2^{x+3}=480\)
c,\(2024^{|x-1|+y^2-1}\cdot3^{2024}=9^{1012}\)
a, 2\(^3\) . x + 2005\(^0\) . x = 994-15:3+1\(^{2025}\)
8 .x + 1 . x = 990
x . [ 8 +1 ] = 990
x . 9 = 990
x = 990 : 9
x = 110
tìm x,y biết
a,\(\left(2^3\right)^{1^{2005}}\cdot x+2005^0\cdot x=9915:3+1^{2025}\)
b,\(2^x+2^{x+1}+2^{x+2}+2^{x+3}=480\)
c,\(2024^{\left|x-1\right|=y^2-1}\cdot3^{2024}=9^{1012}\)
a: \(\left(2^3\right)^{1^{2005}}\cdot x+2005^0\cdot x=9915:3+1^{2025}\)
=>\(8\cdot x+1\cdot x=3305+1\)
=>\(9x=3306\)
=>\(x=\dfrac{3306}{9}=\dfrac{1102}{3}\)
b: \(2^x+2^{x+1}+2^{x+2}+2^{x+3}=480\)
=>\(2^x+2^x\cdot2+2^x\cdot4+2^x\cdot8=480\)
=>\(2^x\left(1+2+4+8\right)=480\)
=>\(2^x\cdot15=480\)
=>\(2^x=32\)
=>\(2^x=2^5\)
=>x+5
1) tìm x biết
a) (x+2)2 + (x – 1)2 + (x -3)(x + 3) – 3x2 = - 8
b) 2022x(x – 2021) – x + 2021 = 0
c) x2 – (x – 3)(2x + 7) = 9
\(a,\Rightarrow x^2+4x+4+x^2-2x+1+x^2-9-3x^2=-8\\ \Rightarrow2x=-4\Rightarrow x=-2\\ b,\Rightarrow\left(x-2021\right)\left(2022x-1\right)=0\\ \Rightarrow\left[{}\begin{matrix}x=2021\\x=\dfrac{1}{2022}\end{matrix}\right.\\ c,\Rightarrow\left(x^2-9\right)-\left(x-3\right)\left(2x+7\right)=0\\ \Rightarrow\left(x-3\right)\left(x+3\right)-\left(x-3\right)\left(2x+7\right)=0\\ \Rightarrow\left(x-3\right)\left(x+3-2x-7\right)=0\\ \Rightarrow\left(x-3\right)\left(-4-2x\right)=0\\ \Rightarrow\left[{}\begin{matrix}x=3\\x=-2\end{matrix}\right.\)