18.\(\left(\dfrac{3737}{4242}+\dfrac{3737}{5656}+\dfrac{3737}{7272}\right)\)

=18.\(\left(\dfrac{37}{42}+\dfrac{37}{56}+\dfrac{37}{72}\right)\)

=18.\(\dfrac{37}{18}\)

=37

`18 . (3737/4242+3737/5656+3737/7272)`

`=18. ( (37.101)/(42.101) + (37.101)/(56.101) + (37.101)/(72.101))`

`=18. (37/42+37/56 +37/72)`

`=18 . 37 . (1/42+1/56+1/72)`

`=18 . 37 . 1/18`

`=37`

\(18\cdot\left(\dfrac{3737}{4242}+\dfrac{3737}{5656}+\dfrac{3737}{7272}\right)\)

\(=18\cdot\left(\dfrac{37\cdot101}{42\cdot101}+\dfrac{37\cdot101}{56\cdot101}+\dfrac{37\cdot101}{72\cdot101}\right)\)

\(=18\cdot\left(\dfrac{37}{42}+\dfrac{37}{56}+\dfrac{37}{72}\right)\)

\(=18\cdot37\cdot\left(\dfrac{1}{42}+\dfrac{1}{56}+\dfrac{1}{72}\right)\)

\(=18\cdot37\cdot\left(\dfrac{1}{6\cdot7}+\dfrac{1}{7\cdot8}+\dfrac{1}{8\cdot9}\right)\)

\(=666\cdot\left(\dfrac{7-6}{6\cdot7}+\dfrac{8-7}{7\cdot8}+\dfrac{9-8}{8\cdot9}\right)\)

\(=666\cdot\left(\dfrac{7}{6\cdot7}-\dfrac{6}{6\cdot7}+\dfrac{8}{7\cdot8}-\dfrac{7}{7\cdot8}+\dfrac{9}{8\cdot9}-\dfrac{8}{8\cdot9}\right)\)

\(=666\cdot\left(\dfrac{1}{6}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{8}+\dfrac{1}{8}-\dfrac{1}{9}\right)\)

\(=666\cdot\left(\dfrac{1}{6}-\dfrac{1}{9}\right)\)

\(=666\cdot\dfrac{1}{18}\)

\(=37\)

=> x - 3/2 = 0 => x = 3/2 ( TH1 )

=> x² + 1 = 0 ; x² = -1

=> x thuộc rỗng

=> x = 3/2

x^2 - 4x + 4 = 5 ( x - 2 ) 

x^2 - 4x + 4 - 5 ( x - 2 ) = 0 

( x - 2 ) ^2 - 5 ( x - 2 ) = 0 

( x - 2 ) ( x - 2 - 5 ) = 0

( x - 2 ) ( x - 7 ) = 0 

x  - 2 = 0 hoặc x - 7 = 0 

x = 2 hoặc x = 7 

c) (x-2)^2=5(x-2)

=> x-2=5 hoặc x-2 =0

=> x=7 hoặc x=2

d) (2x-3)^2=(5-x)^2

=> 2x-3=5-x

=> x=8/3

4x^2 - 12x + 9 = ( 5 - x ) ^2 

( 2x - 3 ) ^2 = ( 5 - x ) ^2 

( 2x - 3 ) ^2 - ( 5 - x ) ^2 = 0 

( 2x - 3 - 5 + x ) ( 2x - 3 + 5 - x ) = 0 

( 3x - 8 ) ( x + 2 ) = 0 

3x - 8 = 0 hoặc x + 2 = 0 

x = 8/3 hoặc x = -2 

a) \(=2\sqrt{5}-3\sqrt{5}+\sqrt{5}-1=-1\)

b) \(=\left[\sqrt{14}+\dfrac{\sqrt{6}\left(\sqrt{2}+\sqrt{5}\right)}{\sqrt{2}+\sqrt{5}}\right].\sqrt{\left(\sqrt{\dfrac{7}{2}}-\sqrt{\dfrac{3}{2}}\right)^2}\)

\(=\left(\sqrt{14}+\sqrt{6}\right)\left(\sqrt{\dfrac{7}{2}}-\sqrt{\dfrac{3}{2}}\right)\)

\(=\sqrt{49}-\sqrt{21}+\sqrt{21}-\sqrt{9}\)

\(=7-3=4\)

a) \(\sqrt{20}-15\sqrt{\dfrac{1}{5}}+\sqrt{\left(1-\sqrt{5}\right)^2}=2\sqrt{5}-3\sqrt{5}+\sqrt{5}-1=-1\)

b) \(\left(\dfrac{14}{\sqrt{14}}+\dfrac{\sqrt{12}+\sqrt{30}}{\sqrt{2}+\sqrt{5}}\right).\sqrt{5-\sqrt{21}}=\left(\sqrt{14}+\sqrt{6}\right)\sqrt{5-\sqrt{21}}=\left(\sqrt{7}+\sqrt{3}\right)\sqrt{10-2\sqrt{21}}=\left(\sqrt{7}+\sqrt{3}\right)\left(\sqrt{7}-\sqrt{3}\right)=4\)

16 teach

17 causes

18 build

19 married

20 fewer

Bình tĩnh chứ bạn, mới có mấy phút

\(A=\dfrac{\left(-3\right)^{45}\cdot5^3\cdot2^{12}}{5^4\cdot3^{44}\cdot\left(-2\right)^{11}}=\dfrac{\left(-3\right)^{45}\cdot\left(-2\right)^{12}}{5\cdot\left(-3\right)^{44}\cdot\left(-2\right)^{11}}=\dfrac{\left(-3\right)\cdot\left(-2\right)}{5}=\dfrac{6}{5}\)

12x-91=101 

suy ra 12x=192

suy ra x=16

minh nhanh nhất đó nhớ bấm đúng cho mình nha

12x-91=101

\(\Rightarrow\)12x=101+91=192

\(\Rightarrow\)x=192:12=16