Tại x = 99

Vì \(x=99\Rightarrow98=x-1\)

Thay \(98=x+1\)vào biểu thức A , ta có :

\(A=x^7-\left(x-1\right)x^6-\left(x-1\right)x^5-\left(x-1\right)x^4-\left(x-1\right)x^3-\left(x-1\right)x^2-\left(x-1\right)x+1\)

\(\Rightarrow A=x^7-x^7+x^6-x^6+x^5-x^5+x^4-x^4+x^3-x^3+x^2-x^2+x+1\)

\(\Rightarrow A=x+1=99+1=100\)

80x20=1600

50x60=3000

70x30=2100

40x90=3600

k mk nha

80x 20= 1600

50x60= 3000

70x30=2100

40x90 =3600

80x20=1600

50x60=3000

70x30=2100

40x90=5400

Đề sai

1

\(2x+4x+6x+........+98x+100x=51.10^2\)

\(\Rightarrow x\left(2+4+6+.........+98+100\right)=51.100\)

\(\Rightarrow x.2550=5100\)

\(\Rightarrow x=5100:2550\)

\(\Rightarrow x=2\)

Vậy x = 2

\(2x+4x+6x+...+100x=51.10^2\)

\(\Rightarrow x\left(2+4+...+100\right)=5100\)

\(\Rightarrow x\left(\frac{\left[\left(100-2\right):2+1\right].\left(100+2\right)}{2}\right)=5100\)

\(\Rightarrow x\left(\frac{50.102}{2}\right)=5100\)

\(\Rightarrow\frac{5100x}{2}=5100\)

\(\Rightarrow5100x=5100.2\)

\(\Rightarrow x=2\)

2x + 4x + 6x + ...+ 98x + 100x = 51.10²

x.(2+4+6+...+98+100) = 51.100

\(x.\left[\left(2+100\right).50:2\right]=5100\)

x. 2550 = 5100

x = 5100 : 2550

x = 2

P(1)=100+99+...+2+1=\(\frac{100\left(100+1\right)}{2}=5050\)

P(1)=5050                                                                                                                                                                                                                                       Hok tốt ~!!!!

thay x=1 

ta có F(1)=100.1^100+99.1^99+98.1^98+...+2.1^2+1

=100+99+98+...+1

=1+2+..+98+99+100

=(100+1).100:2=5050

=>F(x)=5050

=2646

k mik nha chúc các bn ăn tết vui vẻ

98X27=2646

CHÚC MỪNG NĂM MỚI 

Tích là :

98 x 27 = 2646

Đáp số : 2646

k mk nha

happy new year