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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!

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

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

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

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

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

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

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

22 tháng 12 2018

A= \(\frac{1}{x+1}-\frac{1}{x+2}+\frac{1}{x+2}-\frac{1}{x+3}+\frac{2}{x+3}-...+\frac{8}{x+5}-\frac{8}{x+6}\)

A=\(\frac{1}{x+1}+\frac{1}{x+3}+\frac{2}{x+4}+\frac{4}{x+5}-\frac{8}{x+6}\)

Rồi tiếp tục làm nhé bạn.

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

26 tháng 12 2018

đấy là tích không phải tổng nhé

26 tháng 12 2018

Đặt \(A=3\left(x^2+1\right)\left(x^4+1\right)\left(x^8+1\right)\left(x^{16}+1\right)\)

\(\Leftrightarrow\left(x^2-1\right)A=3\left(x^2-1\right)\left(x^2+1\right)\left(x^4+1\right)\left(x^8+1\right)\left(x^{16}+1\right)\)

\(\Leftrightarrow\left(x^2-1\right)A=3\left(x^4-1\right)\left(x^4+1\right)\left(x^8+1\right)\left(x^{16}+1\right)\)

\(\Leftrightarrow\left(x^2-1\right)A=3\left(x^8-1\right)\left(x^8+1\right)\left(x^{16}+1\right)\)

\(\Leftrightarrow\left(x^2-1\right)A=3\left(x^{16}-1\right)\left(x^{16}+1\right)\)

\(\Leftrightarrow\left(x^2-1\right)A=3\left(x^{32}-1\right)\)

\(\Leftrightarrow A=\frac{3\left(x^{32}-1\right)}{x^2-1}\)

1: \(\left(\dfrac{1}{16}\right)^x=\left(\dfrac{1}{8}\right)^6\)

\(\Leftrightarrow\left(\dfrac{1}{2}\right)^{4x}=\left(\dfrac{1}{2}\right)^{18}\)

=>4x=18

hay x=9/2

2: \(\left(\dfrac{1}{16}\right)^x=\left(\dfrac{1}{8}\right)^{36}\)

\(\Leftrightarrow\left(\dfrac{1}{2}\right)^{4x}=\left(\dfrac{1}{2}\right)^{108}\)

=>4x=108

hay x=27

3: \(\left(\dfrac{1}{81}\right)^x=\left(\dfrac{1}{27}\right)^4\)

\(\Leftrightarrow\left(\dfrac{1}{3}\right)^{4x}=\left(\dfrac{1}{3}\right)^{12}\)

=>4x=12

hay x=3

a: Ta có: \(\left(7x+4\right)^2-\left(7x-4\right)\left(7x+4\right)\)

\(=\left(7x+4\right)\left(7x+4-7x+4\right)\)

\(=8\left(7x+4\right)\)

=56x+32

b: Ta có: \(8\left(x-2\right)^2-3\left(x^2-4x-5\right)-5x^2\)

\(=8x^2-32x+32-3x^2+12x+15-5x^2\)

\(=-20x+47\)

c: Ta có: \(\left(x+1\right)^3-\left(x-1\right)\left(x^2+x+1\right)-3x\left(x+1\right)\)

\(=x^3+3x^2+3x+1-x^3+1-3x^2-3x\)

=2

20 tháng 8 2021

câu b cô viết sai đề rồi ạ