A = \(\frac{8}{\sqrt{5}-1}\)  - (\(2\sqrt{5}-1\) ) ( chúng ta cần trục căn thức lên để khử mẫu )                                    

= \(\frac{8\left(\sqrt{5}+1\right)}{5-1}\)- \(\left(2\sqrt{5}-1\right)\)

= \(2\sqrt{5}\)+ 2 - \(2\sqrt{5}\)+1

= 3

B = \(\frac{\left(1-\sqrt{x}\right)^2+4\sqrt{x}}{1+\sqrt{x}}\)( x \(\ge\)0 )

= \(\frac{1-2\sqrt{x}+x+4\sqrt{x}}{1+\sqrt{x}}\)

= \(\frac{1+2\sqrt{x}+x}{1+\sqrt{x}}\)

= \(\frac{\left(1+\sqrt{x}\right)^2}{1+\sqrt{x}}\)

= 1 +\(\sqrt{x}\)

#mã mã#

\(8^{14}:\left(4^4.64^5\right)=2^{42}:\left(2^8.2^{30}\right)=2^{42}:\left(2^{8+30}\right)=2^{42}:2^{38}=2^{42-38}=2^4=16\)

\(\left(9^{10}.27^7\right):\left(81^7.3^{15}\right)=\left(3^{20}.3^{21}\right):\left(3^{28}.3^{15}\right)=\left(3^{20+21}\right)\left(3^{28+15}\right)\)

\(=3^{41}:3^{43}=3^{41-43}=3^{-2}=\frac{1}{9}\)

d. 2^x+2 - 2^x = 96                                                             e. (7x-11)³ = 25 . 5²

=> 2^x.2² - 2^x = 96                                                         => (7x-11)³ = 1000 = 10³  

=> 2^x(2² - 1) = 96                                                         => 7x - 11 = 10

=> 2^x.3 = 2⁵.3                                                               => 7x = 21

=> x = 5                                                                        => x = 3

Câu e đề sai nhé! Mỏi tay ...

d.\(2^{x+2}-2^x=96\) 

  \(2^x\left(2^2-1\right)=96\) 

 \(2^x.3=96\) 

 \(2^x=32=2^5\)

\(\Rightarrow x=5\) 

Vậy.......

e)Đề sai hả bạn ?

a, \(36^2+26^2-52.36=36^2-2.26.36+26^2=\left(36-26\right)^2=10^2=100\)

\(b,2004^2-16^2=\left(2004-16\right)\left(2004+16\right)=1988.2020=4015760\)

\(a,36^2+26^2-52.36\)

\(=36^2-2.26.36+26^2\)

\(=\left(36-26\right)^2\)

\(=10^2=100\)

\(b,2004^2-16^2\)

\(=\left(2004-16\right)\left(2004+16\right)\)

\(=1988.2020\)

\(=4015760\)

\(\left(2x+13\right):5=17\)

\(\Rightarrow2x+13=17.5\)

\(\Rightarrow2x+13=85\)

\(\Rightarrow2x=85-13\)

\(\Rightarrow2x=72\Rightarrow x=\frac{72}{2}=36\)

\(360:\left(11x-7\right)=90\)

\(11x-7=\frac{360}{90}\)

\(\Rightarrow11x-7=4\)

\(\Rightarrow11x=4+7=11\)

\(\Rightarrow x=\frac{11}{11}=1\)

\(30:\left(3x-7\right)=15\)

\(\Rightarrow3x-7=\frac{30}{15}=2\)

\(\Rightarrow3x=2+7=9\)

\(\Rightarrow x=\frac{9}{3}=3\)

a,\(\left(2x+13\right):5=17\)

\(2x+13=17.5\)

\(2x=72\)

\(x=72:2\)

\(x=36\)

b,\(360:\left(11x-7\right)=90\)

\(11x-7=4\)

\(11x=11\)

\(x=1\)

c,\(30:\left(3x-7\right)=15\)

\(3x-7=2\)

\(3x=9\)

\(x=3\)

#)Giải :

\(\left|2-x\right|+2=x\)

\(\Rightarrow\orbr{\begin{cases}\left|2-x\right|=x\\2=x\end{cases}\Rightarrow x=2}\)

Vậy \(x=2\)

\(\left|x-1\right|\left|-x-1\right|=0\)

\(\Rightarrow\orbr{\begin{cases}\left|x-1\right|=0\\\left|-x-1\right|=0\end{cases}\Rightarrow\orbr{\begin{cases}x=1\\x=-1\end{cases}}}\)

Vậy \(x\in\left\{1;-1\right\}\)

2400 là kết quả đúng

2 x 53 x 12 + 4 x 6 x 87 - 3 x 8 x 40

= 1272 + 2088 - 960

= 3360 - 960

= 2400

Đề thiếu không bạn ?

ko bạn, đè như thế

abc+ab+a=1037

= a x 100 + b x 10 + c + a x 10 + b + a = 1037

= a x 111 + b x 11 + c = 1037

= 9 x 111 + 3 x  11 + 5 = 1037

=> a = 9 ; b = 3 ; c = 5

#)Giải :

abc + ab + a = 1037

=> 100a + 10b + c + 10a + b + a = 1037

=> 111a + 11b + c = 1037

=> a = 1037 : 111 = 9 dư 38

=> b = 38 : 11 = 3 dư 5 

=> c = 5 : 1 = 5 

Vậy a = 9; b = 3; c = 5

Số cần tìm là abc = 935