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Thiếu đề : Tính f(2009)

\(F\left(x\right)=x^{98}-\left(x+1\right)x^{97}+\left(x+1\right)x^{96}+...-\left(x+1\right)x^2+\left(x+1\right)x-1\)

\(=x^{98}-x^{98}-x^{97}+x^{97}+x^{96}-x^{96}...-x^3-x^2+x^2+x-1\)

\(=x-1=2009-1=2008\)

3000 :2=?

f(x)=x⁹⁹-3000.x⁹⁸+3000.x⁹⁷-...-3000x²+3000x-1

f(2009)=x⁹⁹-(x+1).x⁹⁸+(x+1).x⁹⁷-...-(x+1)x²+(x+1)x-1

=x⁹⁹-x⁹⁹-x⁹⁸+x⁹⁸+x⁹⁷-...-x³-x²+x²+x-1

=(x⁹⁹-x⁹⁹)+(-x⁹⁸+x⁹⁸)+(x⁹⁷-x⁹⁷)...+(-x²+x²)+x-1

=2009-1

=2008

f(x)=x99-3000.x98+3000.x97-...-3000x2+3000x-1

f(2009)=x99-(x+1).x98+(x+1).x97-...-(x+1)x2+(x+1)x-1

=x99-x99-x98+x98+x97-...-x3-x2+x2+x-1

=(x99-x99)+(-x98+x98)+(x97-x97)...+(-x2+x2)+x-1

=2009-1

=2008

Tính nhẩm:

6000 + 3000 – 5000

= 9000 - 5000

= 4000 

8000 – 3000 – 2000

= 5000 - 2000

= 3000

7000 – (1500 + 4500)

= 7000 - 6000

= 1000

6000 + 2000 – 3000

= 8000 - 3000

= 5000

`6000 + 3000 – 5000= 9000-5000= 4000`

`8000 – 3000 – 2000=5000-2000=3000`

`7000 – (1500 + 4500)=7000-6000=1000`

`6000 + 2000 – 3000=8000-3000=5000`

Ta có : 2999=x => x⁹⁹-3000x⁹⁸⁺3000x⁹⁷-...+3000x-1

f(x) = x⁹⁹ - (x+1)x⁹⁸+(x+1)x⁹⁷-...+(x+1)x-1

=x⁹⁹-x⁹⁹-x⁹⁸+x⁹⁸+x⁹⁷-...x²+x-1=x-1=2999-1=2998

Vậy : f(2999)= 2998

đặt 3000=x+1 ta đc

F(x)=\(x^{98}-\left(x+1\right)x^{97}+\left(x+1\right)x^{96}+...-\left(x+1\right)x^2+\left(x+1\right)x-1=x^{98}-x^{98}-x^{97}+x^{97}+x^{96}-x^{96}.....-x^3-x^2+x^2+x-1=x-1=2009-1=2008\)

vậy.......

ta có:3000=2009+1 \Rightarrow f(2009)=200999200999-3000.200998200998+3000.200997200997-3000.200996200996+...+3000.2009-1 =200999200999-(2009+1)200998200998+(2009+1).200997200997-(2009+1).200996200996+...+(2009+1).2009-1 =200999200999-(200999200999+200998200998)+(200998200998+200997200997)-(200997200997)+.200996200996)+...+(2009220092+2009)-1 =200999200999-200999200999-200998200998+200998200998+200997200997-200997200997-200996200996+...+2009220092+2009-1 =2009-1 =2008

3000+3000=6000

3000+3000=6000

3000 + 3000

= 3000 x 2

= 6000

k cho tớ nha bn

3000:3000+1=2

~~~~~~~

3000 : 3000 + 1

= 1 + 1

= 1 x 2

= 2

~~~~~~~

3000 : 3000 + 1

=  1    +   1

=      2

7000 + 200 = 7200

60 000 + 30 000 = 90 000

8000 - 3000 = 5000

90 000 + 5000 = 95 000

4000 x 2 = 8000

1000 + 3000 x 2 =7000

(1000 + 3000) x 2 = 8000

9000 : 3 + 200 = 3200

7000 + 200 = 7200
60 000 + 30 000 = 90 000
8000 - 3000 = 5000
4000 x 2 = 8000
1000 + 3000 x 2 = 7000
(1000 + 3000 ) x 2 = 8000
9000 : 3 + 200 = 3200

7000 + 200 = 7200

60 000 + 30 000 = 90 000

8000 - 3000 = 5000

90 000 + 5000 = 95 000

4000 x 2 = 8000

1000 + 3000 x 2 =7000

(1000 + 3000) x 2 = 8000

9000 : 3 + 200 = 3200