HOC24
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Chủ đề / Chương
Bài học
\(2016^2-16^2=\left(2016+16\right).\left(2016-16\right)=2032.2000=4064000\)
nếu viết thêm chữ số 0 vào bên phải số bé thì được số lớn suy ra số bé bằng \(\frac{1}{10}\)số lớn
ta có sơ đồ :
số bé : I-----I
số lớn : I-----I-----I-----I-----I-----I-----I-----I-----I-----I-----I
số bé là :
15576 : [ 1 + 10 ] x 1 = 1416
số lớn là :
1416 x 10 = 14160
b)
\(\left(16x^2-9\right).\left(x+1\right)^2=0\)
\(\Rightarrow\left[\left(4x\right)^2-3^2\right].\left(x+1\right)^2=0\)
=> \(\left(4x\right)^2-3^2=0\) hoặc \(\left(x+1\right)^2=0\)
1) \(\left(x+1\right)^2=0\Rightarrow x+1=0\Rightarrow x=-1\)
2) \(\left(4x\right)^2-3^2=0\Rightarrow\left(4x+3\right).\left(4x-3\right)=0\)
=> 4x+3 =0 hoặc 4x-3=0
* 4x+3=0 => 4x=-3 => x= \(\dfrac{-3}{4}\)
* 4x-3=0 => 4x= 3 => x= \(\dfrac{3}{4}\)
Vậy x=-1 ; x=0 ; x=\(\dfrac{-3}{4}\) ; x=\(\dfrac{3}{4}\)
like nha ae !!!!!!!!!!!!!!!!!!
a)
\(\Rightarrow\left[\left(x^3+3^3\right)+\left(x+3\right)\right].\left(x-9\right)=0\)
\(\Rightarrow\left[\left(x+3\right)\left(x^2-3x+3^2\right)+\left(x+3\right)\right].\left(x-9\right)=0\)
\(\Rightarrow\left[\left(x+3\right).\left(x^2-3x+9+1\right)\right].\left(x-9\right)=0\)
\(\Rightarrow\left[\left(x+3\right).\left(x^2-3x+10\right)\right].\left(x-9\right)=0\)
\(\Rightarrow\left(x+3\right)=0\) hoặc x-9=0 hoặc \(x^2-3x+10=0\)
1) x-9=0 => x=9
2) x+3 = 0 => x= -3
3) \(x^2-3x+10=0\Rightarrow x^2-2.x.\dfrac{3}{2}+\dfrac{9}{4}+\dfrac{31}{4}=0\)
\(\Rightarrow\left(x-\dfrac{3}{2}\right)^2+\dfrac{31}{4}=0\Rightarrow\left(x-\dfrac{3}{2}\right)^2=-\dfrac{31}{4}\left(ktm\right)\)
Vậy x=9 ; x=-3
\(\dfrac{x+1}{2015}+\dfrac{x+2}{2014}=\dfrac{x+3}{2013}+\dfrac{x+4}{2012}\)
\(\Rightarrow\dfrac{x+1}{2015}+1+\dfrac{x+2}{2014}+1=\dfrac{x+3}{2013}+1+\dfrac{x+4}{2012}+1\)
\(\Rightarrow\dfrac{x+2016}{2015}+\dfrac{x+2016}{2014}=\dfrac{x+2016}{2013}+\dfrac{x+2016}{2012}\)
\(\Rightarrow\dfrac{x+2016}{2015}+\dfrac{x+2016}{2014}-\dfrac{x+2016}{2013}-\dfrac{x+2016}{2012}=0\)
\(\Rightarrow\left(x+2016\right).\left(\dfrac{1}{2015}+\dfrac{1}{2014}-\dfrac{1}{2013}-\dfrac{1}{2012}\right)=0\)
do \(\dfrac{1}{2015}+\dfrac{1}{2014}-\dfrac{1}{2013}-\dfrac{1}{2012}\ne0\)
\(\Rightarrow x+2016=0\Rightarrow x=2016\)
váy x=2016
câu 1
f(x) = \(x^2+x+1\)
g(x)=\(x^4+x^3+x^2+x+1\)
\(\Rightarrow f\left(x\right).g\left(x\right)=\left(x^2+x+1\right)\left(x^4+x^3+x^2+x+1\right)\)
\(=x^6+x^5+x^4+x^3+x^2+x^5+x^4+x^3+x^2+x+x^4+x^3+x^2+x+1\)
\(=x^6+2x^5+3x^4+3x^3+3x^2+x+1\)
=> f(x).g(x) có bậc là 6
Câu 2
ta có \(A=x^2-2x-1\Rightarrow A=x^2-2x+1-2\)
\(A=\left(x-1\right)^2-2\ge-2\)
dấu bằng xảy ra khi A đạt GTNN bằng -2
\(\left(x-1\right)^2=0\Rightarrow x=1\)
Vây A đạt GTNN là -2 tại x=1
like nha ae !!!!
ta có \(35^{2005}-35^{2004}=35^{2004}.35-35^{2004}=35^{2004}.\left(35-1\right)=35^{2004}.34\)
do \(34⋮17\Rightarrow35^{2004}.34⋮17\left(đpcm\right)\)