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6 tháng 9 2018

nốt ý b:

\(\left(x-1\right)^3+1+3x\left(x-4\right)=0\)

\(\Leftrightarrow x^3-3x^2+3x-1+1+3x^2-12x=0\)

\(\Leftrightarrow x^3-9x=0\Leftrightarrow x\left(x^2-9\right)=0\)

\(\Leftrightarrow x\left(x-3\right)\left(x+3\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x-3=0\\x+3=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=3\\x=-3\end{matrix}\right.\)

Vậy ..............

6 tháng 9 2018

\(a,x\left(x-2012\right)-2013x+2012.2013=0\)

\(=x\left(x-2012\right)+2013\left(-x+2012\right)=0\)

\(\Rightarrow x\left(x-2012\right)-2013\left(x-2012\right)=0\)

\(\Rightarrow\left(x-2013\right)\left(x-2012\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}x-2013=0\\x-2012=0\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=2013\\x=2012\end{matrix}\right.\)

Vậy...

16 tháng 9 2023

\(Bài.1:\\ a,104^2-16=104^2-4^2=\left(104+4\right)\left(104-4\right)=108.100=10800\\ b,9^8.2^8-\left(18^4-1\right)\left(18^4+1\right)\\ =\left(9.2\right)^8-\left(18^8-1\right)=18^8-18^8+1=1\\ c,999^3+3.999^2+3.999+1\\ =999^3+3.999^2.1+3.999.1^2+1^3=\left(999+1\right)^3=1000^3=1000000000\\ d,42^3-6.42^2+12.42-8\\ =42^3-3.42^2.2+3.42.2^2-2^3\\ =\left(42-2\right)^3=40^3=64000\)

16 tháng 9 2023

Bài 1

a) 104² - 16

= 104² - 4²

= (104 - 4)(104 + 4)

= 100.108

= 10800

b) 9⁸.2⁸ - (18⁴ - 1)(18⁴ + 1)

= 18⁸ - (18⁸ - 1)

= 18⁸ - 18⁸ + 1

= 1

c) 999³ + 3.999² + 3.999 + 1

= (999 + 1)³

= 1000³

= 1000000000

d) 42³ - 6.42² + 12.42 - 8

= (42 - 2)³

= 40³

= 64000

30 tháng 5 2020

f(x) = x2013 - 2013x2012 + 2013x2011 - 2013x2010 + .... + 2013x - 1 

= x2013 - (2012 + 1)x2012 + (2012 + 1)x2011 - (2012 + 1)x2010 + .... + (2012 + 1)x - 1 

= x2013 - (x + 1)x2012 + (x + 1)x2011 - (x + 1)x2010 + .... + (x + 1)x - 1 

= x2013 - x . x2012 - 1 . x2012 + x . x2011 + 1 . x2011 - x . x2010 - 1 . x2010 + ... + x . x + 1 . x - 1

= x2013 - x2013 - x2012 + x2012 + x2011 - x2011 - x2010 + .... + x2 + x - 1

= x - 1 = 2012 - 1 = 2011

x=2012

nên x+1=2013

\(f\left(x\right)=x^{2013}-x^{2012}\left(x+1\right)+x^{2011}\left(x+1\right)-...-x^2\left(x+1\right)+x\left(x+1\right)-1\)

\(=x^{2013}-x^{2013}-x^{2012}+x^{2012}-...-x^3-x^2+x^2+x-1\)

=x-1

=2012-1=2011

x=2012

nên x+1=2013

\(f\left(x\right)=x^{2013}-x^{2012}\left(x+1\right)+x^{2011}\left(x+1\right)-...+x\left(x+1\right)-1\)

\(=x^{2013}-x^{2013}-x^{2012}+x^{2012}+x^{2011}-...+x^2+x+1\)

=x+1=2013

5 tháng 7 2016

Đặt \(g\left(x\right)=x^{2015}-x^{2014}+x^{2013}-...+x-1\)

Dễ thấy: \(f\left(x\right)=x^{2016}-2013\times g\left(x\right)\Rightarrow f\left(2012\right)=2012^{2016}-2013\times g\left(2012\right)\)(a)

Ta có: \(\left(x+1\right)\times g\left(x\right)=\left(x+1\right)\left(x^{2015}-x^{2014}+x^{2013}-...+x-1\right)\)

\(\Rightarrow\left(x+1\right)\times g\left(x\right)=x^{2016}-1\)

\(\Rightarrow\left(2012+1\right)\times g\left(2012\right)=2012^{2016}-1\)hay: \(2013\times g\left(2012\right)=2012^{2016}-1\)

Thay vào (a) ta có: \(f\left(2012\right)=2012^{2016}-\left(2012^{2016}-1\right)=1\).