a) 35-{12-[-14+(-2)]}.

= 35 - 12 + 14 + 2

= 35 + 14 - (12 - 2)

= 49 - 10

= 39

b) 160:{17+[9×5-(14+2048:256)]}.

= 160: {17 + [45 - (14 + 8)]}

= 160: {17 + [45 - 22)]}

= 160:{17 + 23}

= 160: 40 = 4

c) 2021⁰-{225:[20×15-8×25]-25}.

= 1 - {225:[300 - 200] - 25}

= 1 - {225 : 100 - 25}

= 1 - {2,25 - 25}

= 1 + 25 - 2,25

= 23,75

a, \(\sqrt{\dfrac{289}{225}}=\sqrt{\dfrac{17^2}{15^2}}=\dfrac{17}{15}\)

b, \(\sqrt{2\dfrac{14}{25}}=\sqrt{\dfrac{64}{25}}=\sqrt{\dfrac{8^2}{5^2}}=\dfrac{8}{5}\)

c, \(\sqrt{\dfrac{0,25}{9}}=\sqrt{\dfrac{0,5^2}{3^2}}=\dfrac{0,5}{3}\)

d, \(\sqrt{\dfrac{8,1}{1,6}}=\sqrt{\dfrac{0,1}{0,1}.\dfrac{81}{16}}=\sqrt{1.\dfrac{81}{16}}=\dfrac{9}{4}\)

Chúc bạn học tốt!!!

a) \(\sqrt{\dfrac{289}{225}}\)

\(=\dfrac{\sqrt{289}}{\sqrt{225}}\)

\(=\dfrac{\sqrt{17^2}}{\sqrt{15^2}}\)

\(=\dfrac{17}{15}\)

b) \(\sqrt{2\dfrac{14}{15}}\)

\(=\sqrt{\dfrac{44}{15}}\)

\(=\dfrac{\sqrt{44}}{\sqrt{15}}\)

\(=\dfrac{2\sqrt{11}}{\sqrt{15}}\)

\(=\dfrac{2\sqrt{165}}{15}\)

c) \(\sqrt{\dfrac{0,25}{9}}\)

\(=\sqrt{\dfrac{1}{\dfrac{4}{9}}}\)

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

\(=\dfrac{1}{6}\)

d) \(\sqrt{\dfrac{8,1}{1,6}}\)

\(=\sqrt{5,0625}\)

\(=\sqrt{\dfrac{81}{16}}\)

\(=\dfrac{9}{4}\)

a) ; b) ;

c) ; d) .

a) \(\sqrt{\dfrac{289}{225}}=\dfrac{\sqrt{289}}{\sqrt{225}}=\dfrac{17}{15}\)

b) \(\sqrt{2\dfrac{14}{25}}=\dfrac{\sqrt{64}}{\sqrt{25}}=\dfrac{8}{5}\)

c) \(\sqrt{\dfrac{0,25}{9}}=\dfrac{\sqrt{0,25}}{\sqrt{9}}=\dfrac{0,5}{3}=\dfrac{1}{6}\)

d) \(\sqrt{\dfrac{8,1}{1,6}}=\dfrac{\sqrt{81}}{\sqrt{16}}=\dfrac{9}{4}\)

\(\sqrt{\dfrac{49}{100}}=\dfrac{7}{10}\\ \sqrt{\dfrac{144}{289}}=\dfrac{12}{17}\\ \dfrac{\sqrt{36}}{\sqrt{225}}=\dfrac{6}{15}=\dfrac{2}{5}\\ \dfrac{\sqrt{25}}{\sqrt{121}}=\dfrac{5}{11}\)

`\sqrt{49/100}=\sqrt{(7/10)^2}=7/10`

`\sqrt{144/289}=\sqrt{(12/17)^2}=12/17`

`\sqrt{36/225}=\sqrt{(6/15)^2}=6/15`

`\sqrt{25/121}=\sqrt{(5/11)^2}=5/11`

a: =>3x=10+14=24

=>x=8

b: =>25-30-x=-19

=>-5-x=-19

=>x+5=19

=>x=14

c: =>15-x=12+14=26

=>x=-11

d: =>4x+11-x-34=67

=>3x-23=67

=>3x=90

=>x=30

e: =>-x-14=289-36-289=-36

=>x+14=36

=>x=22

a) 3x=24
     x=8
b) 25-30-x=-19
    25-30+19=x
     14=x
c) 15-x=26
         x=-11
d) 4x+11-x-34=67
    3x=90
      x=30
e) -14-x= -36
          x=-14 -36
          x= 22
      
 

a, \(\sqrt{\frac{289}{25}}=\frac{\sqrt{289}}{\sqrt{25}}=\frac{17}{5}\)

b, \(\sqrt{2\frac{14}{25}}=\sqrt{\frac{64}{25}}=\frac{8}{5}\)

c, \(\sqrt{\frac{0,25}{9}}=\frac{\sqrt{0,25}}{\sqrt{9}}=\frac{0,5}{3}=\frac{1}{2}.\frac{1}{3}=\frac{1}{6}\)

d, \(\sqrt{\frac{8,1}{16}}\)đề có sai ko cô ? 

a) căn 289 / 225 = 17/15

b) căn 64/ 25 = 8/5

c) căn 0,25 / 9 = 1/6

d) căn 8,1 / 1,6 = 9/4

289225=289225=1715.

1425=2.25+1425=6425=6425=85.

0,259=0,259=0,53=530=16.

8,11,6=8116=8116=94.

1) ( cái này tính máy tính là ra nha pn )

a)105

b) 100

c)2006

2)

a) => 7x =2390/ 17

=>x=2390/ 119

b) =>7(x-14) = (25+279:9) -35

=> 7(x-14) =21

=> x-14 =3

=> x=17
( click đúng và kết bạn với tớ nha )
 

1/ a/ \(3-\left(17-x\right)=289-\left(36+289\right)\)

\(3-\left(17-x\right)=-36\)

\(17-x=3-\left(-36\right)\)

\(x=17-39=-22\)

b/ \(25-\left(x+5\right)=415-\left(15-415\right)\)

\(25-\left(x+5\right)=815\)

\(x+5=25-815\)

\(x=\left(-790\right)-5=-795\)

c/ \(\left|x-7\right|+13=25\)

\(\left|x-7\right|=25-13=12\)

\(\left|x-7\right|\Rightarrow\left[{}\begin{matrix}x-7=12\\x-7=-12\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=19\\x=-5\end{matrix}\right.\)

Câu 2:

a) (a - 1) - (a - 3) = a - 1 - a + 3 = 2

b) (2 + b) - (b + 1) = 2 + b - b - 1 = 1

a) 225 - ( -45 ) - 100

=225+45-100

=270-100

=170

b) | - 25 | + | 25 | - ( - 50 )

=25+25+50

=50+50

=100

c) 25 - 5. [( -4 )² + 4 ] . ( -1)⁵

=25-5.[(-16)+4].(-5)

=25-5.(-12).(-5)

=25-(-60).(-5)

=25-300

=-275

tick nha

a)225 -(-45) -100

  =225  +45 -100

  =170

b) |-25| +|25| - (-50)

   =25+25+50

    =(25+25)+50

=50+50=100

a. 24 x (-125 + 225)

= 24 x 100

=2400

b. -125 x ( 24 -36 )

= -125 x -12

= 1500

c. 512 x (2 -128+128)

= 512 x 2

= 1024

d. \([4.25].\left[\left(-2\right).\left(-5\right)\right].\left[125.\left(-8\right)\right]\)

= 100.10.(-1000)

= -1000000

a. 24 x (-125 + 225)

= 24 x 100

=2400

b. -125 x ( 24 -36 )

= -125 x -12

= 1500

c. 512 x (2 -128+128)

= 512 x 2

= 1024

d. $[4.25].\left[\left(-2\right).\left(-5\right)\right].\left[125.\left(-8\right)\right]$

= 100.10.(-1000)

= -1000000