`1/2 xx x +3/2 =7`

`=> 1/2 xx x = 7-3/2`

`=> 1/2 xx x = 14/2 -3/2`

`=> 1/2 xx x = 11/2`

`=> x= 11/2 :1/2`

`=> x=11/2 xx2`

`=> x= 22/2`

`=>x=11`

Vậy `x=11`

__

`3/2 xx x -2/7 xx(x-7/2)=18`

`=> 3/2 xx x -2/7x + 1=18`

`=> (3/2 -2/7 )x+ 1 =18`

`=> 17/14 x=18-1`

`=> 17/14x=17`

`=>x=17:17/14`

`=> x=17 xx 14/17`

`=>x=14`

a) \(\dfrac{1}{2}\times x+\dfrac{3}{2}=7\)

\(\dfrac{1}{2}\times x=7-\dfrac{3}{2}\)

\(\dfrac{1}{2}\times x=\dfrac{11}{2}\)

\(x=\dfrac{11}{2}\div\dfrac{1}{2}\\ x=\dfrac{11}{2}\times2\\ x=\dfrac{22}{2}=11\)

b) \(\dfrac{3}{2}\times x-\dfrac{2}{7}\times\left(x-\dfrac{7}{2}\right)=18\)

\(\dfrac{3}{2}\times x-\left(\dfrac{2}{7}x-1\right)=18\)

\(\dfrac{3}{2}\times x-\dfrac{2}{7}x+1=18\)

\(\dfrac{3}{2}x-\dfrac{2}{7}x+1=18\)

\(\dfrac{17}{14}x+1=18\)

\(\dfrac{17}{14}x=18-1\)

\(\dfrac{17}{14}x=17\)

\(x=17\div\dfrac{17}{14}\)

\(x=17\times\dfrac{14}{17}\)

\(x=14\)

a) \(\dfrac{1}{2}\times x+\dfrac{3}{2}=7\)

\(\Leftrightarrow\dfrac{1}{2}\times x=7-\dfrac{3}{2}\)

\(\Leftrightarrow\dfrac{1}{2}\times x=\dfrac{11}{2}\)

\(\Leftrightarrow x=\dfrac{11}{2}:\dfrac{1}{2}\)

\(\Leftrightarrow x=\dfrac{11}{2}\times\dfrac{2}{1}\)

\(\Rightarrow x=11\)

b) \(\dfrac{3}{2}\times x-\dfrac{2}{7}\times\left(x-\dfrac{7}{2}\right)=18\)

\(\Leftrightarrow\dfrac{3}{2}\times x-\dfrac{7}{2}\times x+1=18\)

\(\Leftrightarrow\left(\dfrac{3}{2}-\dfrac{7}{2}\right)\times x+1=18\)

\(\Leftrightarrow\dfrac{17}{14}\times x=18-1\)

\(\Leftrightarrow\dfrac{17}{14}\times x=17\)

\(\Leftrightarrow x=17:\dfrac{17}{14}\)

\(\Leftrightarrow x=17\times\dfrac{14}{17}\)

\(\Rightarrow x=14\)

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

a: \(=12\sqrt{2}+5\cdot3\sqrt{2}-3\cdot5\sqrt{2}-2\cdot4\sqrt{2}\)

\(=12\sqrt{2}-8\sqrt{2}=4\sqrt{2}\)

b: \(=\sqrt{\left(\sqrt{3}+1\right)^2}+\sqrt{\left(5-\sqrt{3}\right)^2}\)

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

=6

d, D = 40² - 28² + 32² +80.32

    D = (40² + 2.40.32 + 32²) - 28²

    D = (40 + 32)² - 28²

    D = (40 + 32 - 28)(40 + 32 + 28)

    D = 44.100

   D = 4400

  e, E = 10.80,5 + 10.19,5 - 8.20,5 - 8. 79,5

      E =  10.(80,5 + 19,5) - 8.( 20,5 + 79,5)

      E = 10.100 - 8.100

     E = 100.(10-8)

     E = 200

F = 50² - 18² + 32² + 100.32

F = (50² - 18²) + 32.( 32 + 100)

F = (50 -18)(50+18) + 32. 132

F = 32.68 + 32.132

F = 32.( 68 + 132)

F = 32. 200

F = 6400

dài thế

dai the giai bao gio xong chac mua quyt nam sau moi giai xong

1,   15-(2x-3)=6

<=>2x-3=15-6

<=>2x=15-6+3

<=>2x=12

<=>x=12:2

<=>x=6

Vậy x=6

2,   (x-2).3=3\(^2\)

<=>x-2=3\(^2\):3

<=>x-2=9:3

<=>x=9:3-2

<=>x=1

vậy x=1

3,   (x+7)-25=13

<=>x+7=13+25

<=>x=13+25-7

<=>x=31

Vậy x=31

4,   450:(x-190)=50

<=>x-190=450:50

<=>x=450:50+/ 190

<=>x=199

Vậy x=199

5,     3 \(^x\)x 2=18

<=>3\(^x\)=18:2

<=>3\(^x\)=9=3\(^2\)

=>x=2

vậy x=2