1+90x9+80+232=?
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232 x 68 + 232 x 31 + 232
= 232 x ( 68 + 31 + 1 )
= 232 x 100
= 23200
a, \(P=\left(\frac{x+1}{x}-\frac{1}{1-x}+\frac{2-x^2}{x^2-x}\right):\frac{x}{x-1}\)ĐK : \(x\ne0;1\)
\(=\left(\frac{x^2-1+x+2-x^2}{x\left(x-1\right)}\right).\frac{x-1}{x}=\frac{x+1}{x^2}\)
b, Ta có : \(\left|2x-1\right|=3\Leftrightarrow\orbr{\begin{cases}2x-1=3\\2x-1=-3\end{cases}\Leftrightarrow\orbr{\begin{cases}x=2\\x=-1\end{cases}}}\)( tmđk )
TH1 : Thay x = 2 vào biểu thức P ta được : \(\frac{2+1}{4}=\frac{3}{4}\)
TH2 : Thay x = -1 vào biểu thức P ta được : \(\frac{-1+1}{1}=0\)
Trả lời:
a, \(P=\left(\frac{x+1}{x}-\frac{1}{1-x}+\frac{2-x^2}{x^2-x}\right):\frac{x}{x-1}\)\(\left(đkxđ:x\ne0;x\ne1\right)\)
\(=\left[\frac{x+1}{x}+\frac{1}{x-1}+\frac{2-x^2}{x\left(x-1\right)}\right]:\frac{x}{x-1}\)
\(=\left[\frac{\left(x+1\right)\left(x-1\right)}{x\left(x-1\right)}+\frac{x}{x\left(x-1\right)}+\frac{2-x^2}{x\left(x-1\right)}\right]\cdot\frac{x-1}{x}\)
\(=\frac{\left(x+1\right)\left(x-1\right)+x+2-x^2}{x\left(x-1\right)}\cdot\frac{x-1}{x}\)
\(=\frac{x^2-1+x+2-x^2}{x\left(x-1\right)}\cdot\frac{x-1}{x}\)
\(=\frac{x+1}{x\left(x-1\right)}\cdot\frac{x-1}{x}\)
\(=\frac{\left(x+1\right)\left(x-1\right)}{x\left(x-1\right)x}\)
\(=\frac{x+1}{x^2}\)
b, \(\left|2x-1\right|=3\)
Ta có: \(\left|2x-1\right|=\hept{\begin{cases}2x-1\left(đk:x>\frac{1}{2}\right)\\1-2x\left(đk:x< -\frac{1}{2}\right)\end{cases}}\)
Giải 2 pt:
+) 2x - 1 = 3 với x > 1/2
<=> 2x = 4
<=> x = 2 ( tm )
+) 1 - 2x = 3 với x < -1/2
<=> - 2x = 2
<=> x = - 1 ( tm )
Vậy x = 2; x = - 1
Thay x = 2 vào P, ta có:
\(P=\frac{2+1}{2^2}=\frac{3}{4}\)
Thay x = -1 vào P, ta có:
\(P=\frac{-1+1}{\left(-1\right)^2}=0\)
a) Ta có: \(\left(2+1\right)\left(2^2+1\right)\left(2^4+1\right)\left(2^8+1\right)\left(2^{16}+1\right)\)
\(=\left(2-1\right)\left(2+1\right)\left(2^2+1\right)\left(2^4+1\right)\left(2^8+1\right)\left(2^{16}+1\right)\)
\(=\left(2^2-1\right)\left(2^2+1\right)\left(2^4+1\right)\left(2^8+1\right)\left(2^{16}+1\right)\)
\(=\left(2^4-1\right)\left(2^4+1\right)\left(2^8+1\right)\left(2^{16}+1\right)\)
\(=\left(2^8-1\right)\left(2^8+1\right)\left(2^{16}+1\right)\)
\(=\left(2^{16}-1\right)\left(2^{16}+1\right)\)
\(=2^{32}-1\)
232 - 582 - ( 232 - 81)
= 232 - 582 - 232 + 81
= ( 232 - 232 ) - ( 582 - 81)
= 0 - 501
= - 501
232 - (230 + 232 - 350)
=232 - (-230) - 232 + 350
=462 - 232 + 350
=230 + 350
=580
Ta có
N = ( 2 + 1 ) ( 2 2 + 1 ) ( 2 4 + 1 ) ( 2 8 + 1 ) ( 2 16 + 1 ) ( 2 16 + 1 ) = 3 ( 2 2 + 1 ) ( 2 4 + 1 ) ( 2 8 + 1 ) ( 2 16 + 1 ) = [ ( 2 2 – 1 ) ( 2 2 + 1 ) ] ( 2 4 + 1 ) ( 2 8 + 1 ) ( 2 16 + 1 ) = ( 2 4 – 1 ) ( 2 4 + 1 ) ( 2 8 + 1 ) ( 2 16 + 1 ) = ( 2 8 – 1 ) ( 2 8 + 1 ) ( 2 16 + 1 ) = ( 2 16 - 1 ) ( 2 16 + 1 ) = 2 16 2 − 1 = 2 32 − 1 M à 2 32 − 1 > 2 32 ⇒ N < M
Đáp án cần chọn là: A