16x=256
15x=625
2x+1=128
28-x=512
3x+2=343
DT
Những câu hỏi liên quan
Tìm x:
( 4x + 1 )( 16x^2 - 4x + 1 ) - 16x ( 4x^2 - 5 ) = 17
Tính giá trị biểu thức:
p=(x+1)(x^2-x+1)+x-(x-1)(x^2+x+1)+2010; x=-2010)
q=16x(4x^2-5)-(4x+1)(16x^2-4x+1); x=1/5
\(p=\left(x+1\right)\left(x^2-x+1\right)+x-\left(x-1\right)\left(x^2+x+1\right)+2010\)\(=\left(x^3+1\right)+x-\left(x^3-1\right)+2010=x^3+1+x-x^3+1+2010=x+2012\)Với \(x=-2010\Rightarrow p=-2010+2012=2\)
\(q=16x\left(4x^2-5\right)-\left(4x+1\right)\left(16x^2-4x+1\right)=64x^3-80x-64x^3-1=-80x-1\)Với \(x=\dfrac{1}{5}\Rightarrow q=-80.\dfrac{1}{5}-1=-17\)
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38. Chọn câu sai:
A. 16x^2 (x-y) - x + y= (2x-1) (2x+1)(4x^2+1)(x-y)
B. 16x^3 - 54y^5 = 2(2x -3y) (4x^2 + 6xy + 9y^2)
C. 16x^5 - 54y = 2(2x-3y) (2x + 3y)^2
D. 16x^4 (x-y) - x + y = (4x^2 -1 (4x^2 +1) (x-y)
C) 5x-(4-2x+x^2)(x+2)+x (x-1)(x+1)=0
D) (4x+1)(16x^2-4x+1)-16x (4x^2-5)=17
giải
5x-(4-2x+x^2)(x+2)+x(x-1)(x+1)=0
5x-(4x+8-2x^2-4x+x^3+2x^2)+x(x^2-1)=0
5x-4x-8+2x^2+4x-x^3-2x^2+x^3-1x=0
(5x-4x+4x-1x)+(-8)+(2x^2-2x^2)+(-x^3+x^3)=0
4x+(-8)=0
4x=0+8
4x=8
x=8:4
x=2
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D)(4x+1)(16x^2-4x+1)-16x(4x^2-5)=17
64x^3-16x^2+4x+16x^2-4x+1-64x^3+80x=17
80x+1=17
80x=17-1
80x=16
x=1/5
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\(5x-\left(4-2x+x^2\right)\left(x+2\right)+x\left(x-1\right)\left(x+1\right)=0\)
\(\Rightarrow5x-\left(4x-2x^2+x^3+8-4x+2x^2\right)+\left(x^2-x\right)\left(x+1\right)=0\)
\(\Rightarrow5x-\left(4x-2x^2+x^3+8-4x+2x^2\right)+\left(x^3+x-x^2-x\right)=0\)
\(\Rightarrow5x-4x+2x^2-x^3-8+4x-2x^2+x^3+x-x^2-x=0\)
\(\Rightarrow4x-8=0\Rightarrow4x=8\Rightarrow x=2\)
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(4x+1)(1-4x+16x^2) - 16x(4x^2-5) = 17 tim x
\(\left(4x+1\right)\left(1-4x+16x^2\right)-16x\left(4x^2-5\right)=17\)
\(\Leftrightarrow4x-16x^2+64x^2+1-4x+16x^2-64x^2+80x-17=0\)
\(\Leftrightarrow\left(-16x^2+16x^2\right)+\left(64x^2-64x^2\right)+\left(4x-4x\right)+80x+1-17=0\)
\(\Leftrightarrow80x=16\)
\(\Leftrightarrow x=\dfrac{1}{5}\)
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Tìm x: 4x+1.(16x2-4x+1)-16x.(x2-5)=17
Tìm x: 4x+1.(16x2-4x+1)-16x.(x2-5)=17
tìm x : (4x+1)(16x^2-4x+1)-16x(4x^2-5)=17
64x^3 + 1 - 64x^3 + 80x =17
80x =16
x =3/10
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64x^3 + 1 -64x^3 + 80x = 17
80x = 16
x = 3/10
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64x^3 + 1 - 64x^3 + 80x = 17
80x = 16
x = 3/10
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(2.x+1)mux3=343
`#3107.101107`
`(2x + 1)^3 = 343`
`\Rightarrow (2x + 1)^3 = 7^3`
`\Rightarrow 2x + 1 = 7`
`\Rightarrow 2x = 6`
`\Rightarrow x = 3`
Vậy, `x = 3.`
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7^x+2 + 7^x-1 = 343
\(\sqrt[5]{\frac{16x}{x-1}}+\sqrt[5]{\frac{x-1}{16x}}=\frac{5}{2}\)
ĐKXĐ: \(x\ne\left\{0;1\right\}\)
Đặt \(\sqrt[5]{\frac{16x}{x-1}}=t\)
\(\Rightarrow t+\frac{1}{t}=\frac{5}{2}\Leftrightarrow2t^2-5t+2=0\Rightarrow\left[{}\begin{matrix}t=2\\t=\frac{1}{2}\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}\sqrt[5]{\frac{16}{x-1}}=2\\\sqrt[5]{\frac{16}{x-1}}=\frac{1}{2}\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}\frac{16x}{x-1}=32\\\frac{16x}{x-1}=\frac{1}{32}\end{matrix}\right.\)
\(\Rightarrow x=...\)