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14 tháng 1 2016

-x^61+5*x^60+x^59-5*x^58-x^55+5*x^54+x^53-5*x^52-x^49+5*x^48+x^47-5*x^46x^43+5*x^42+x^41-5*x^40-x^37+5*x^36+x^35-5*x^34-x^49+5*x^48+x^47-5*x^46x^43+5*x^42+x^41-5*x^40-x^37+5*x^36+x^35-5*x^34-x^31+5*x^30+x^27-5*x^26-x^25+5*x^24+x^21-5*x^20-x^19+5*x^18+x^15-5*x^14-x^13+5*x^12+x^9-5*x^8-x^7+5*x^6+x^3-5*x^2-x+5

8 tháng 11 2016

a)(x+1)(x+2)(x+3)(x+4)+1

=(x+1)(x+4)(x+2)(x+3)+1

=(x2+5x+4)(x2+5x+6)+1

Đặt a=(x2+5x+4) thì (x2+5x+4)(x2+5x+6)+1

= a.(a+2)+1

=a2+2a+1

=(a+1)2

Thay: =(x2+5x+4+1)2

=(x2+5x+5)2

b)(x+2)(x+4)(x+6)(x+8)+16

=(x+2)(x+8)(x+4)(x+6)+16

=(x2+10x+16)(x2+10x+24)+16

Đặt a=(x2+10x+16) thì (x2+10x+16)(x+5x+24)+1

= a.(a+8)+16

=a2+8x+16

=(a+4)2

Thay: =(x2+10x+16+4)2

=(x2+5x+20)2

2 tháng 7 2019

a)(x+1)(x+2)(x+3)(x+4)+1

=[(x+1)(x+4][(x+2)(x+3)]+1

=(x2+5x+4)(x2+5x+6)+1

Đặt a=(x2+5x+4)

Ta có: (x2+5x+4)(x2+5x+6)+1

= a.(a+2)+1

=a2+2a+1

=(a+1)2

=(x2+5x+4+1)2

=(x2+5x+5)2

b)(x+2)(x+4)(x+6)(x+8)+16

=(x+2)(x+8)(x+4)(x+6)+16

=(x2+10x+16)(x2+10x+24)+16

Đặt a=(x2+10x+16)

Ta có:(x2+10x+16)(x+5x+24)+1

= a.(a+8)+16

=a2+8x+16

=(a+4)2

=(x2+10x+16+4)2

=(x2+5x+20)2

Mk yêu bé Shin-Conan lémyeuyeu

AH
Akai Haruma
Giáo viên
22 tháng 9 2020

a)

$A=(1^2-2^2)+(3^2-4^2)+....+(2003^2-2004^2)+2005^2$

$=(1-2)(1+2)+(3-4)(3+4)+....+(2003-2004)(2003+2004)+2005^2$

$=-(1+2)-(3+4)-...-(2003+2004)+2005^2$

$=-(1+2+3+...+2004)+2005^2=-\frac{2004.2005}{2}+2005^2$

$=2005^2-1002.2005=2005(2005-1002)=2011015$

b)

$B=(2-1)(2+1)(2^2+1)(2^4+1)(2^8+1)(2^{16}+1)(2^{32}+1)-2^{64}$

$=(2^2-1)(2^2+1)(2^4+1)(2^8+1)(2^{16}+1)(2^{32}+1)-2^{64}$

$=(2^4-1)(2^4+1)(2^8+1)(2^{16}+1)(2^{32}+1)-2^{64}$

$=(2^8-1)(2^8+1)(2^{16}+1)(2^{32}+1)-2^{64}$

$=(2^{16}-1)(2^{16}+1)(2^{32}+1)-2^{64}$

$=(2^{32}-1)(2^{32}+1)-2^{64}$

$=2^{64}-1-2^{64}=-1$

AH
Akai Haruma
Giáo viên
22 tháng 9 2020

c) Do $x=16$ nên $x-16=0$

$R(x)=x^4-17x^3+17x^2-17x+20$

$=(x^4-16x^3)-(x^3-16x^2)+x^2-16x-x+20$

$=x^3(x-16)-x^2(x-16)+x(x-16)-x+20$

$=x^3.0-x^2.0+x.0-x+20=-x+20=-16+20=4$

d) Do $x=12$ nên $x-12=0$. Khi đó:

$S(x)=(x^{10}-12x^9)-(x^9-12x^8)+(x^8-12x^7)-....+(x^2-12x)-x+10$

$=x^9(x-12)-x^8(x-12)+x^7(x-12)-....+x(x-12)-x+10$

$=(x-12)(x^9-x^8+x^7-....+x)-x+10$

$=0-x+10=-x+10=-12+10=-2$

28 tháng 2 2020

Bài 1:

\(a, \dfrac{1}{2}x(2-x)=x-\dfrac{1}{2}x^2\)

\(b, \dfrac{x-5}{5-x}\)\(=-\dfrac{x-5}{x-5}\)\(=-1\)

Bài 2:

\(a, x+y-x^2+y^2=(x+y)-(x^2-y^2)=(x+y)-(x-y)(x+y)\)

\(=(x+y)(1-x+y)\)

\(b, x(x-3)+3x-1=0 \)

\(⇔x^2-3x+3x-1=0 \)

\(⇔x^2-1=0 \)

\(⇔(x-1)(x+1)=0 \)

\(⇔\left[\begin{array}{} x-1=0\\ x+1=0 \end{array}\right.\)

\(⇔\left[\begin{array}{} x=1\\ x=-1 \end{array}\right.\)

Bài 3:

\(a,A=\dfrac{x(x+2)-x(x-2)+8}{x^2-4}:\dfrac{4}{x-2}\)

\(A=\dfrac{4x+8}{(x-2)(x+2)}.\dfrac{x-2}{4}\)

\(A=\dfrac{4(x+2)}{(x-2)(x+2)}.\dfrac{x-2}{4}\)

\(A=1\)

\(b, B=(1-\dfrac{a+b}{a-b})(1-\dfrac{2b}{a+b})\)

\(B=\dfrac{-2b}{a-b}.\dfrac{a-b}{a+b}\)

\(B=\dfrac{-2b}{a+b}\)

Bài 4:

\(C=(2+1)(2^2+1)(2^4+1)(2^8+1)(2^{16}+1)(2^{32}+1)\)

\(C=(2^2-1)(2^2+1)(2^4+1)(2^8+1)(2^{16}+1)(2^{32}+1)\)

\(C=(2^4-1)(2^4+1)(2^8+1)(2^{16}+1)(2^{32}+1)\)

\(C=(2^8-1)(2^8+1)(2^{16}+1)(2^{32}+1)\)

\(C=(2^{16}-1)(2^{16}+1)(2^{32}+1)\)

\(C=(2^{32}-1)(2^{32}+1)=2^{64}-1\)

28 tháng 2 2020

Thanks bạn nha!!!!ok

b: Ta có: \(\left(x+2\right)\left(x+3\right)\left(x+4\right)\left(x+5\right)-24=0\)

\(\Leftrightarrow\left(x^2+7x+10\right)\left(x^2+7x+12\right)-24=0\)

\(\Leftrightarrow\left(x^2+7x\right)^2+22\left(x^2+7x\right)+120-24=0\)

\(\Leftrightarrow x^2+7x+6=0\)

\(\Leftrightarrow\left(x+1\right)\left(x+6\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=-1\\x=-6\end{matrix}\right.\)

2 tháng 1 2021

Ta có: \(\left(x-1\right)\left(x+1\right)\left(x^2+1\right)\left(x^4+1\right)\left(x^8+1\right)\left(x^{16}+1\right)\)

\(=\left(x^2-1\right)\left(x^2+1\right)\left(x^4+1\right)\left(x^8+1\right)\left(x^{16}+1\right)\)

\(=\left(x^4-1\right)\left(x^4+1\right)\left(x^8+1\right)\left(x^{16}+1\right)\)

\(=\left(x^8-1\right)\left(x^8+1\right)\left(x^{16}+1\right)\)

\(=\left(x^{16}-1\right)\left(x^{16}+1\right)\)

\(=x^{32}-1\)

Bạn tham khảo nhé!

26 tháng 9 2019

Vế trái: 4/(x+2).(x+6)+7/(x+6).(x+13)

<=>1/x+2 -1/x+6 +1/x+6 -1/x+13

<=>1/x+2-1/x+13

=> 1/x+2-1/x+13=2x+1/(x+2).(x+16) -3/(x+13).(x+16)

<=>1/x+2 - 1/x+13 + 1/x+13 - 1/x+16=2x+1/(x+2).(x+16)

<=>1/x+2 - 1/x+16=2x+1/(x+2).(x+16)

<=> 14/(x+2).(x+16)= 2x+1/(x+2).(x+16)

<=> 2x+1=14

<=> 2x=14-1

<=> 2x=13

<=> x=13:2

<=> x=13/2

Vậy x=13/2

Chúc bạn học tốt