a) To solve for x, we need to isolate it on one side of the equation.

x + (-2/9) = -7/12

First, we can simplify the equation by adding the fractions on the left side:

x - 2/9 = -7/12

Next, we can get rid of the fraction by multiplying both sides of the equation by the common denominator, which is 36:

36(x - 2/9) = 36(-7/12)

This simplifies to:

36x - 8 = -21

Now, we can isolate x by adding 8 to both sides of the equation:

36x = -21 + 8

36x = -13

Finally, we divide both sides of the equation by 36 to solve for x:

x = -13/36

b) To solve for x, we need to isolate it on one side of the equation.

(-0,1) - x = -7/6

First, we can simplify the equation by subtracting the fraction on the right side:

-0.1 - x = -7/6

Next, we can isolate x by adding x to both sides of the equation:

-0.1 = x - 7/6

Now, we can simplify the equation by finding a common denominator:

-0.1 = (6x - 7)/6

To get rid of the fraction, we can multiply both sides of the equation by 6:

6(-0.1) = 6(6x - 7)/6

This simplifies to:

-0.6 = 6x - 7

Next, we can isolate x by adding 7 to both sides of the equation:

-0.6 + 7 = 6x - 7 + 7

6.4 = 6x

Finally, we divide both sides of the equation by 6 to solve for x:

x = 6.4/6

x = 1.067

c) To solve for x, we need to isolate it on one side of the equation.

(-0.12) * (x - 9/10) = -1.2

First, we can simplify the equation by multiplying the fractions:

-0.12x + 0.108 = -1.2

Next, we can isolate x by subtracting 0.108 from both sides of the equation:

-0.12x = -1.2 - 0.108

-0.12x = -1.308

Finally, we divide both sides of the equation by -0.12 to solve for x:

x = -1.308 / -0.12

x = 10.9

d) To solve for x, we need to isolate it on one side of the equation.

(x - 3/5) / (-1/3) = 0.4

First, we can simplify the equation by dividing the fractions:

(x - 3/5) * (-3/1) = 0.4

Next, we can simplify the equation by multiplying:

-3(x - 3/5) = 0.4

Now, we can distribute the -3:

-3x + 9/5 = 0.4

Next, we can isolate x by subtracting 9/5 from both sides of the equation:

-3x = 0.4 - 9/5

-3x = 0.4 - 1.8

-3x = -1.4

Finally, we divide both sides of the equation by -3 to solve for x:

x = -1.4 / -3

x = 0.4667