b: \(\dfrac{4^5\cdot9^4-2\cdot6^9}{2^{10}\cdot3^8+6^8\cdot20}\)

\(=\dfrac{2^{10}\cdot3^8-2^{10}\cdot3^9}{2^{10}\cdot3^8+3^8\cdot2^{10}\cdot5}\)

\(=\dfrac{2^{10}\cdot3^8\left(1-3\right)}{2^{11}\cdot3^9}\)

\(=\dfrac{1}{2}\cdot\dfrac{-2}{3}=\dfrac{-1}{3}\)

Sửa đề câu a) phải là (-2020/2021)⁰

Xin lỗi mn

\(a,=\dfrac{3}{4}+\dfrac{15}{6}\cdot\dfrac{1}{5}-\dfrac{1}{36}\cdot9-\dfrac{2020}{2021}=\dfrac{3}{4}+\dfrac{1}{2}-\dfrac{1}{4}-\dfrac{2020}{2021}=1-\dfrac{2020}{2021}=\dfrac{1}{2021}\\ b,=\dfrac{2^{10}\cdot3^8-2\cdot2^9\cdot3^9}{2^{10}\cdot3^8+2^8\cdot3^8\cdot2\cdot5}=\dfrac{2^{10}\cdot3^8\left(1-3\right)}{2^9\cdot3^8\left(2+5\right)}=\dfrac{2\left(-2\right)}{3}=-\dfrac{4}{3}\)

a: \(A=2^{100}-2^{99}+2^{98}-2^{97}+...+2^2-2\)

=>\(2A=2^{101}-2^{100}+2^{99}-2^{98}+...+2^3-2^2\)

=>\(2A+A=2^{101}-2^{100}+2^{99}-2^{98}+...+2^3-2^2+2^{100}-2^{99}+...+2^2-2\)

=>\(3A=2^{101}-2\)

=>\(A=\dfrac{2^{101}-2}{3}\)

b: Sửa đề: \(A=\dfrac{2\cdot8^4\cdot27^2+4\cdot6^9}{2^7\cdot6^7+2^7\cdot40\cdot9^4}\)

\(A=\dfrac{2\cdot2^{12}\cdot3^6+2^2\cdot2^9\cdot3^9}{2^7\cdot2^7\cdot3^7+2^7\cdot2^3\cdot5\cdot3^8}\)

\(=\dfrac{2^{11}\cdot3^6\left(2^3+3^3\right)}{2^{10}\cdot3^7\left(2^4+5\cdot3\right)}\)

\(=\dfrac{2}{3}\cdot\dfrac{4+27}{16+15}=\dfrac{2}{3}\)

c: \(B=\dfrac{4^5\cdot9^4-2\cdot6^4}{2^{10}\cdot3^8+6^8\cdot20}\)

\(=\dfrac{2^{10}\cdot3^8-2\cdot2^4\cdot3^4}{2^{10}\cdot3^8+2^8\cdot2^2\cdot5\cdot3^8}\)

\(=\dfrac{2^5\cdot3^4\left(2^5\cdot3^4-1\right)}{2^{10}\cdot3^8\left(1+5\right)}=\dfrac{1}{2^5\cdot3^4}\cdot\dfrac{32\cdot81-1}{6}\)

\(=\dfrac{2591}{2^6\cdot3^5}\)

help

sao nhieu qua zay

Ơ WTF

Biểu thức =\(\frac{15}{34}+\frac{4}{27}+\frac{19}{34}+\frac{23}{27}\)  ( rút gọn đó )

              =\(\left(\frac{15}{34}+\frac{19}{34}\right)+\left(\frac{4}{27}+\frac{23}{27}\right)\)

              =\(\frac{15+19}{34}+\frac{4+23}{27}\)= \(\frac{34}{34}+\frac{27}{27}\)

              = \(1+1=2\)

Oke nhá !!

=2.Hết gấp nha

bang 2

d+ 0 =1. vậy d = 0+1 =1

c + 1 =0. vậy c= 0-1=-1

b + (-1) =1. vậy b=1-(-1) = 2

a + 2 =-1. vậy a= -1-2=-3

suy ra x(x-4)=x hoặc -x

th1:x(x-4)=x

      x-4=x:x=1

suy ra x=1+4 =5

th2:x(x-4)=-x

       x-4=-x:x=-1

suy ra x=-1+4=3

vậy x=5 hoặc 3

nhớ k mình nha

ta có x lớn hơn hoặc bằng 0 

|x(x-4)|=x => |x| . |x-4| = x 

vì x > hoặc = 0 => |x | = x => x|x-4|=x => x|x-4|-x=0 => x (|x-4| - 1 ) = 0 => x = 0 hoặc |x-4| - 1 =0 
tự làm tiếp phần còn lại nhé nhok

|x(x - 4)| = x

\(\Rightarrow\orbr{\begin{cases}x\left(x-4\right)=x\\x\left(x-4\right)=-x\end{cases}}\Rightarrow\orbr{\begin{cases}x-4=1\\x-4=-1\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=5\\x=3\end{cases}}\)

x bằng 5 hoặc 3

mình thấy đáp án x = 0 đúng mà sao 2 bạn làm ko có th x=0

Lời giải:

\(P=\frac{2^{19}.27^3+15.4^9.9^4}{6^9.2^{10}+12^{10}}\\ =\frac{2^{19}.3^9+3.5.2^{18}.3^8}{2^9.3^9.2^{10}+2^{20}.3^{10}}\\ =\frac{2^{19}.3^9+2^{18}.3^9.5}{2^{19}.3^9+2^{20}.3^{10}}\\ =\frac{2^{18}.3^9(2+5)}{2^{19}3^9(1+2.3)}\\ =\frac{1}{2}\)