Câu a:

x + 1/2 = - 3/4

x = - 3/4 - 1/2

x = - 3/4 - 2/4

x = -5/4

Vậy x = - 5/4

Câu b:

-6/5 = 2/x

x = 2: - 6/5

x = 2.(-5/6)

x = - 5/3

Vậy x = - 5/3

Câu c:

(2 - 3x)/8 = 2/(2 - 3x)

(2 - 3x)^2 = 8.2

(2 - 3x)^2 = 16

2 - 3x = -4 hoặc 2 - 3x = 4

2 - 3x = - 4

3x = 2 + 4

3x = 6

x = 6 : 3

x = 2

2 - 3x = 4

3x = 2 - 4

3x = - 2

x = -2/3

Vậy x ∈ {-2/3; 2}

a) => 4/3x = 7/9 - 4/9 = 1/3

=> x = 1/3 : 4/3 = 1/4

b) => 5/2 - x = 9/14 : (-4/7) = -9/8

=> x = 5/2 - (-9/8) = 5/2 + 9/8 = 29/8

c) => 3x = 2 và 2/3 - 3/4 = 8/3 - 3/4 = 23/12

=> x = 23/12 : 3 = 23/36

D) => -5/6 - x = 1/4

=> x = -5/6 - 1/4 = -13/12

a) \(\dfrac{4}{9}+\dfrac{4}{3}x=\dfrac{7}{9}\)

\(\dfrac{4}{3}x=\dfrac{7}{9}-\dfrac{4}{9}=\dfrac{1}{3}\)

\(x=\dfrac{1}{3}:\dfrac{4}{3}\)

\(x=\dfrac{1}{4}\)

b) \(\left(\dfrac{5}{2}-x\right)\left(-\dfrac{4}{7}\right)=\dfrac{9}{14}\)

\(\dfrac{5}{2}-x=\dfrac{9}{14}:\left(-\dfrac{4}{7}\right)=-\dfrac{9}{8}\)

\(x=\dfrac{5}{2}-\left(-\dfrac{9}{8}\right)\)

\(x=\dfrac{29}{8}\)

c) \(3x+\dfrac{3}{4}=2\dfrac{2}{3}\)

\(3x+\dfrac{3}{4}=\dfrac{8}{3}\)

\(3x=\dfrac{8}{3}-\dfrac{3}{4}=\dfrac{23}{12}\)

\(x=\dfrac{23}{12}:3\)

\(x=\dfrac{23}{36}\)

d) \(-\dfrac{5}{6}-x=\dfrac{7}{12}+\dfrac{-1}{3}\)

\(-\dfrac{5}{6}-x=\dfrac{1}{4}\)

\(x=-\dfrac{5}{6}-\dfrac{1}{4}\)

\(x=-\dfrac{13}{12}\)

Câu a:

xem lại đề bài

Câu b:

5 2/8x - 1/9 = 4 3/5

42/8x - 1/9 = 23/5

21/4x = 23/5 + 1/9

21/4x = 207/45 + 5/45

21/4x = 212/45

x = 212/45: 21/4

x = 212/45 x 4/21

x = 848/945

Vậy: x = 848/945

Câu c:

45%x - 2/3x = 75%

9/20x - 2/3x = 3/4

x(9/20 - 2/3) = 3/4

x(27/60 - 40/60) = 3/4

x.(-13/60) = 3/4

x = 3/4 : (-13/60)

x = 3/4 x (-60/13)

x = - 45/13

Vậy x = - 45/13

a: \(A=x^2+2+3x^2+2-2x^2-2=2x^2+2\)

b: \(B=2x-3-\left(3x-2\right)-\left(2x-4\right)\)

\(=2x-3-3x+2-2x+4=-3x+3\)

c: \(C=6-3x+3x+10=16\)

d: \(D=\left|3x-8\right|+\left|x+2\right|\)

\(=3x-8+x+2=4x-6\)

a) \(\frac{3x}{-4}=\frac{-9}{6}\)

=> \(\frac{-3x}{4}=\frac{-9}{6}\)

=> \(\frac{-3x}{4}=\frac{-3}{2}\)

=> \(\frac{-3x}{4}=\frac{-6}{4}\)

=> \(-3x=-6\)

=> \(x=\left(-6\right):\left(-3\right)=2\)

b) \(\frac{2}{x}=\frac{y}{10}=\frac{4}{-5}\)

=> \(\frac{2}{x}=\frac{y}{10}=\frac{-4}{5}\)

+) \(\frac{2}{x}=\frac{-4}{5}\)

=> \(\left(-4\right)\cdot x=2\cdot5\)

=> \(\left(-4\right)\cdot x=10\)

=> \(x=\frac{10}{-4}=\frac{-10}{4}=\frac{-5}{2}\)

+) \(\frac{y}{10}=\frac{-4}{5}\)

=> \(5\cdot y=-40\)

=> \(y=\left(-40\right):5=-8\)

Vậy \(x=-\frac{5}{2},y=-8\)

c) \(\frac{7}{-x}=\frac{5}{y}=\frac{2}{34}\)

=> \(\frac{-7}{x}=\frac{5}{y}=\frac{1}{17}\)

+) \(\frac{-7}{x}=\frac{1}{17}\Rightarrow x=\left(-7\right)\cdot17=-119\)

+) \(\frac{5}{y}=\frac{1}{17}\Rightarrow y=5\cdot17=85\)

Vậy \(x=-119,y=85\)

d) \(\frac{x^2}{4}=16\)

=> \(x^2=16\cdot4=64\)

=> \(x\in\left\{8;-8\right\}\)

e) \(\frac{3}{x^3}=\frac{4}{-36}\)

=> \(\frac{3}{x^3}=\frac{1}{-9}=\frac{-1}{9}\)

=> \(x^3=3:\left(-\frac{1}{9}\right)=-27\)

=> \(x=-3\)

Vậy x = -3

a,\(\frac{1}{3}x=-2-\frac{2}{3}=\frac{-8}{3}\)

        \(x=\frac{-8}{3}:\frac{1}{3}=\frac{-8}{3}.\frac{3}{1}=-8\)

\(b,\left[x+\frac{1}{1}\right]^2+\frac{5}{6}=\frac{7}{8}\)

\(\Rightarrow\left[x+1\right]^2=\frac{7}{8}-\frac{5}{6}\)

\(\Rightarrow\left[x+1\right]^2=\frac{7\cdot3}{24}-\frac{5\cdot4}{24}\)

\(\Rightarrow\left[x+1\right]^2=\frac{21}{24}-\frac{20}{24}\)

\(\Rightarrow\left[x+1\right]^2=\frac{1}{24}\)

\(\Rightarrow x\in\left\{\varnothing\right\}\)

Bài 1

a, =5.(-24)

    =-12

b,=4+25

   =29

Bài 2:Tìm số nguyên x

a,x-2=-6+17

=> x-2= 11

=> x = 11 + 2

=> x = 13

b,x+2=-9

=> x = -9 - 2

=> x = -11