$\displaystyle 1.2\left ( 6.4 y\right ) = 69.12$  

Use distributive property, multiply $\displaystyle 1.2$ and $\displaystyle 6.4$

 $\displaystyle 7.68y = 69.12$   

Divide both sides by $\displaystyle 7.68$

$\displaystyle y=9$

To isolate the unknown variable, first subtract one from both sides.

$\displaystyle -0.2x+1 -(1)= 0.2-(1)$

$\displaystyle -0.2x =-0.8$

Divide by $\displaystyle -0.2$ on both sides of the equation.

$\displaystyle \frac{-0.2}{-0.2}x =\frac{-0.8}{-0.2}$

$\displaystyle x=4$

The goal is to solve for x. To do this we need to get x by itself. There are two terms on the same side of the equation with the variable we want isolate. We must cancel them out.

$\displaystyle 0.75x-0.25=1.25$

Add the term not attached to x to both sides:

$\displaystyle 0.75x{\color{Red} -0.25+0.25}=1.25+0.25$

The red terms cancel out and we add as usual on the right side of the equation.

$\displaystyle 0.75x=1.50$

Now divide both sides by $\displaystyle 0.75$ to completely isolate x:

$\displaystyle \frac{{\color{Red} 0.75}x}{{\color{Red} 0.75}}=\frac{1.5}{.75}$

The red terms cancel to 1. The right side is divided as normal. A short cut for dividing decimals is to relate them to coins or convert them to fractions. On the right side we have $1.50 in the numerator and .75 cents in the denominator. It takes two sets of .75 cents to make a $1.50. So x=2.

If this analogy does not work then convert the decimals to fractions. Three divided by two is 1.5 and 3 divided by 4 is .75. When we divide a fraction by a fraction we multiply the numerator by the reciprocal of the denominator. $\displaystyle \frac{3}{2}*\frac{4}{3}=\frac{12}{6}=2$

If either of these methods are not easily applicable to the problem, seem like too much work, or are too abstract, then move the decimal of the divisor to make it a whole number. Then move the decimal of the dividend the same number of decimal places. Now divide as usual.

Using this method on the right side of our equation:

$\displaystyle \frac{{\color{Red} 0.75}x}{{\color{Red} 0.75}}=\frac{1.5}{.75}\rightarrow x=\frac{1.5}{{\color{Blue} 75}}=\frac{{\color{Green} 150}}{75}=2$

With a two step equation don't forget when solving the problem do the inverse operation. That means opposite of addition is subtraction and vice versa and opposite of multiplication is division and vice versa. Make sure what ever you do to one side you do to the other as well. Tip: Do addition or subtraction first, then multiplication or division.

$\displaystyle 6.75x + 12 = 93$

             $\displaystyle {\color{Red} - 12 - 12}$

$\displaystyle \frac{6.75x}{{\color{Red}6.75 }} = \frac{81}{{\color{Red}6.75 }}$

$\displaystyle x = 12$

Check your answer by substituting x back into the equation. Both sides should equal.             

In order to solve the equation, we have to isolate the variable. We do this by performing the same operation to either side of the equation.

To isolate the unknown variable, first subtract $\displaystyle 0.5$ from both sides.

$\displaystyle 0.5x + 0.5-(0.5) = -1.5-(0.5)$

$\displaystyle 0.5x =-2$

Divide both sides by $\displaystyle 0.5$.

$\displaystyle \frac{0.5x}{0.5} =\frac{-2}{0.5}$

$\displaystyle x=-4$

If dividing by a decimal if difficult, multiply the numerator and denominator by ten to get whole integers.

$\displaystyle \frac{-2\cdot 10}{0.5\cdot 10}=\frac{-20}{5}$

Now factor the numerator to find a common factor to cancel out.

$\displaystyle \frac{-20}{5}=\frac{-4\cdot 5}{5}=-4$

To isolate  the unknown variable, first subtract $\displaystyle 0.75$ from both sides.

$\displaystyle 0.25x +0.75 -0.75= 1-0.75$

$\displaystyle 0.25x= 0.25$

$\displaystyle x=1$

To solve for the unknown variable, first subtract $\displaystyle 0.05$ from both sides of the equation.

$\displaystyle 0.5x =0.95$

Divide $\displaystyle 0.5$ on both sides.

$\displaystyle \frac{0.5x}{0.5} =\frac{0.95}{0.5}$

$\displaystyle x=1.9$

If dividing by decimals is difficult, just multiply both decimals by 100 to get integers.

$\displaystyle \frac{0.95\times 100}{0.5\times100} = \frac{95}{50}$

When you multiply by 100 you move the decimal two spaces to the right.

From here factor the numerator and cancel like terms.

$\displaystyle \frac{95}{50}=1.9$

In order to solve the equation, we have to isolate the variable. We do this by performing the same operation to either side of the equation.

Subtract $\displaystyle 0.3$ from both sides of the equation.

$\displaystyle 0.03x +0.3 -0.3 = 0.03-0.3$

$\displaystyle 0.03x =-0.27$

Divide $\displaystyle 0.03$ on both sides.

$\displaystyle x= -9$

In order to solve the equation, we have to isolate the variable. We do this by performing the same operation to either side of the equation.

To solve for $\displaystyle x$, combine like-terms by subtracting.

$\displaystyle -0.1x = 0.5$

Divide both sides by $\displaystyle -0.1$.

$\displaystyle \frac{-0.1x }{-0.1}= \frac{0.5}{-0.1}$

Decimals may be written as fractions. 

$\displaystyle -0.1=-\frac{1}{10}$ 

$\displaystyle 0.5=\frac{1}{2}$

Dividing by a fraction is the same as multiplying by its reciprocal:

Thus we can replace the decimals with their fraction equivalents:

$\displaystyle x=\frac{1}{2}\times -\frac{10}{1}=\frac{-10}{2}=\frac{-5\cdot 2}{2}$

Canceling out the two that is in the numerator and in the denominator we arrive at our final answer.

$\displaystyle x= -5$

Subtract $\displaystyle 0.02$ from both sides of the equation.

$\displaystyle 0.02+2x-0.02 = 0.2-0.02$

$\displaystyle 2x=0.18$

Divide by two on both sides.

$\displaystyle \frac{2x}{2}=\frac{0.18}{2}$

$\displaystyle x=0.09$