phần mik gửi vừa nãy là vt nhầm , nên mik gửi lại

\(A=\left(8^{200}-8^{199}\right):8^{198}+\left(7^{25}.7^{20}\right):7^{43}\)

\(\Rightarrow A=8^{199}\left(8^1-1\right):8^{198}+7^{45}:7^{43}\)

\(\Rightarrow A=8.7+7^2=56+49=105\)

A = (1000.1) - 999 = 1

B = 100

C: Nhận xét: 16 - 2x8 = 16 - 16 = 0 mà số nào nhân với 0 cũng bằng 0 => C = 0

A:1

B:100

C:0

C

C

c

a, 4*113*25-5*112*20=(4*25)*113-(5*20)*112=100*113-100*112=100*(113-112)=100

b, 2+4+...........+98+100-(1+3+...........+99)=[(100-2)/2+1*102]-[(99-1)/2+1*100]

 =98/2+1*102-98/2+1*100=(98/2+1)*(102-100)=(49+1)*2=50*2=100

4x113x25-5x112x20

= ( 4x25 )x113-(5x20)x112

=100x113-100x112

=100x(113-112)

=100x1

=100

=100+100+1000

=1200

1200 à? Mik tính nhẩm đó

20 + 25 + 20 + 100 + 200 + 300 + 400 + 25 + 25 + 25 + 20 + 20 + 20

= 20 x 5 + 25 x 4 + 100 + 100 x 2 + 100 x 3 + 100 x 4

= 100 x 1 + 100 x 1 + 100 x 1 + 100 x 2 + 100 x 3 + 100 x 4

= 100 x ( 1 + 1 + 1 + 2 + 3 + 4 )

= 100 x 12

= 1200

\(5^{200}=\left(5^2\right)^{100}=25^{100}\)

\(3< 25=>3^{100}< 25^{100}=>3^{100}< 5^{200}\)

\(\frac{75^{20}}{45^{10}.25^{15}}=\frac{25^{20}.3^{20}}{3^{10}.3^{10}.5^{10}.25^{15}}=\frac{25^{20}}{25^5.25^{15}}=1\)

\(=>75^{20}=45^{10}.25^{15}\left(dpcm\right)\)

P/S:nếu a=b=>a:b=1 mk làm theo cách đó cho nhanh mà bn ghi sai đề r

a) 4% x 5% = 20% .....Đ.                                      c) 25% x 8% = 2% ......S.

b) 4% x 5% = 0,2% ......S                                      d) 25% x 8% = 200%....Đ.......

a)Đ

b)S

c)S

d)Đ

a, 200 - 3( x - 16 ) = 20

        3( x - 16 )     = 200 - 20 = 180

             x - 16     = 180 : 3 = 60 

                 x        = 60 + 16  =  76

b, 5 + 10 + 15 + .............. + 95 + 100 + 105 = 1200

c, x + ( 99 - 97 + 95 - 93 + ............ + 7 - 5 + 3 - 1 ) = 100

       x + ( 2 . 25 ) = 100

         x + 50       = 100

             x           = 100 - 50 = 50

****, thks