a) 35 - x = 16 - (-2) =>35 - x = 18 => x = 17

b) x - 2 = (-7) -9 => x - 2 = -16 => x = -14

Câu 1:

\(\frac{x+16}{35}=\frac{x}{7}\)

\(\frac{x+16}{35}=\frac{5x}{35}\)

\(x+16=5x\)

\(5x-x=16\)

\(4x=16\)

\(x=\frac{16}{4}\)

\(x=4\)

Câu 2:

\(-2x^2+40=-10\)

\(-2x^2=-10-40\)

\(-2x^2=-50\)

\(x^2=\frac{-50}{-2}\)

\(x^2=25\)

\(x^2=\left(\pm5\right)^2\)

\(x=\pm5\)

Vậy x = 5 hoặc x = - 5.

Chúc bạn học tốt

a) \(\dfrac{x}{-6}=\dfrac{-15}{45}\)

    \(\dfrac{-x}{6}=\dfrac{-15}{45}\)

    \(\dfrac{x}{6}=\dfrac{15}{45}\)

    \(x=\dfrac{\left(15\cdot6\right)}{45}\)

    \(x=2\)

b) \(\dfrac{x}{5}=\dfrac{16}{25}\)

    \(x=\dfrac{\left(16\cdot5\right)}{25}\)

    \(x=\dfrac{80}{25}\)

   \(x=\dfrac{16}{5}\)

c) \(\dfrac{5}{x-3}=\dfrac{20}{-12}\)

  \(x-3=\dfrac{\left(5\cdot-12\right)}{20}\)

 \(x-3=-3\)

 \(x=\left(-3\right)+3\)

\(x=0\)

d) \(\dfrac{2}{5}\cdot x=\dfrac{6}{35}\)

         \(x=\dfrac{6}{35}\div\dfrac{2}{5}\)

        \(x=\dfrac{3}{7}\)

a: =>16/x=-4/5

hay x=-20

b: =>x+7/15=-2/3

=>x+7=-10

hay x=-17

x = 35 : 7 = 5

x = 16 + 4 = 20

x = 20 : 5 

x = 4

tích trước trả lời sau

Ta có : (x + 16).7 = 35x

      => 16x + 112 = 35x

     => 112 = 35x - 16x

     => 19x = 112

     => x = 112 : 19

\(a.\)

\(\dfrac{-28}{35}=\dfrac{16}{x}\)

\(\Rightarrow x=\dfrac{35\cdot16}{-28}=\dfrac{5\cdot7\cdot4\cdot4}{-7\cdot4}=-20\)

\(b.\)

\(\dfrac{x+7}{15}=\dfrac{-24}{36}\)

\(\Rightarrow x+7=\dfrac{15\cdot-24}{36}=\dfrac{5\cdot3\cdot-12\cdot2}{12\cdot3}=-10\)

\(\Leftrightarrow x=-17\)

a, - ( x + 84 ) + 213 = -16

=> - ( x + 84 ) = -16 - 213

=>  - ( x + 84 ) =-229

=> x + 84 = 229

=> x = 145

b.  x + ( -35 ) = 18

=> x = 18 - ( -35 )

=> x = 18 + 35

=> x = 53

c. -2x - ( - 17 ) = 15

=> -2x = 15 + ( -17)

=> -2x = -2 

=> x = 1

\(a,-\left(x+84\right)+213=-16\)

                             \(x+84=213+16\)

                             \(x+84=229\)

                                        \(x=229-84\) 

                                        \(x=145\)

\(b,x+\left(-35\right)=18\)

                        \(x=18+35\)

                        \(x=53\)

\(c,-2x-\left(-17\right)=15\)

               \(-2x+17=15\)

                              \(2x=17-15\)         

                              \(2x=2\)

                                 \(x=1\)

Tìm số nguyên x, biết:
1) -16 + 23 + x = - 16

7+x=-16

    x=-16-7

    x=-23
2) 2x – 35 = 15

2x=15+35

2x=50

  x=50:2

  x=25
3) 3x + 17 = 12

3x=12-17

3x=-5

  x=-5/3
4) (2x – 5) + 17 = 6

2x-5=6-17

2x-5=-11

2x=-11+5

2x=-6

  x=-6:2

  x=-3
5) 10 – 2(4 – 3x) = -4

2(4-3x)=10-(-4)

2(4-3x)=14

4-3x=14:2

4-3x=7

3x=4-7

3x=-3

  x=-3:3

  x=-1
6) - 12 + 3(-x + 7) = -18

3(-x+7)=-18-(-12)

3(x+7)=-6

x+7=-6:3

x+7=-2

    x=-2-7

    x=-9

tự đi mà làm