ghi lại đề tý

\(B=x^{15}-8x^{14}+8x^{13}-8x^2+...-8x^2+8x-5\)

=> \(B=x^{15}-\left(x+1\right)x^{14}+\left(x+1\right)x^{13}-\left(x+1\right)x^{12}+...+\left(x+1\right)x-x+2\)

=>\(B=x^{15}-x^{15}+x^{14}-x^{14}+x^{13}-x^{13}-x^{12}+...+x^2+x-x+2\\\)

=>B=2

x bằng bao nhiêu

B = x15 - 8x14 + 8x13 - 8x2 + ... - 8x2 + 8x - 5

B = x^15 - 7x^14 -x^14+7x^13+x^13-7x^12-...-x^2+7x+x-5

B = x^14(x-7) - x^14(x-7) +...+x^2(x-7)-x(x-7)+x-5

B = 7-5=2

`B = x^15 - 7x^14 - x^14 + 7x^13 + x^13 - .... +7x + x - 7 + 2`

`<=> x^14(x-7) - x^13(x-7) + ... + x - 7 + 2`

`<=> (x^14-x^13 + ... + 1)(x-7) + 2`

Thay `x = 7 <=> (x^14 - x^13 + ... + 1) xx 0 + 2 = 2`.

B = \(x^{15}-8x^{14}+8x^{13}+8x^2+...-8x^2+8x-5\)

B = \(x^{15}-7x^{14}+x^{14}+7x^{13}+x^{13}+7x^{12}-...-x^2+7x+x-5\)

B = \(x^{14}\left(x-7\right)-x^{14}\left(x-7\right)+...+x^2\left(x-7\right)-x\left(x-7\right)-5\)

B = \(7-5=2\)

ta có: 8=7+1=x+1

\(B=x^{15}-8x^{14}+8x^{13}-...-8x^2+8x-5\)

\(\Rightarrow B=x^{15}-\left(x+1\right)x^{14}+\left(x+1\right)x^{13}-...-\left(x+1\right)x^2+\left(x+1\right)x-5\)

\(\Rightarrow B=x^{15}-x^{15}-x^{14}+x^{14}+x^{13}-...-x^3-x^2+x^2+x-5\)

\(\Rightarrow B=x-5\)

\(\Rightarrow B=7-5\)

\(\Rightarrow B=2\)

B = x15 - 8x14 + 8x13 - 8x2 + ... - 8x2 + 8x - 5

B = x^15 - 7x^14 -x^14+7x^13+x^13-7x^12-...-x^2+7x+x-5

B = x^14(x-7) - x^14(x-7) +...+x^2(x-7)-x(x-7)+x-5

B = 7-5=2

B = x15 - 8x14 + 8x13 - 8x2 + ... - 8x2 + 8x - 5

B = x^15 - 7x^14 -x^14+7x^13+x^13-7x^12-...-x^2+7x+x-5

B = x^14(x-7) - x^14(x-7) +...+x^2(x-7)-x(x-7)+x-5

B = 7-5=2

Tham khảo cách này nhoá~

\(\dfrac{8x^2-8x+2}{\left(4x-2\right)\left(15-x\right)}=\dfrac{2\left(4x^2-4x+1\right)}{\left(4x-2\right)\left(15-x\right)}=\dfrac{2\left(2x-1\right)^2}{2\left(2x-1\right)\left(15-x\right)}=\dfrac{2x-1}{15-x}=\dfrac{1-2x}{x-15}\Rightarrow?=x-15\)

Lấy kết quả của 3/8 x 2 rồi trừ cho kết quả của 6/7 + 1/3

\(\dfrac{3}{8}\times2-\dfrac{6}{7}+\dfrac{1}{3}=\dfrac{3}{4}-\dfrac{6}{7}+\dfrac{1}{3}=\dfrac{19}{84}\)

3/8 x 2 - 6/7 + 1/3

= 3/4 - 6/7 + 1/3

= -3/28 + 1/3

= 19/84

=1/24:3/4+5/3                                                                                                                                                =1/18+5/3                                                                                                                                                     =31/18                                                                                                                                                           Ủng hộ nka!!!!!

1/8*2/6:3/4+5/3

=1/8*1/3:3/4+5/3

=1/24*4/3+5/3

=1/18+30/18

=31/18