1.398 = 2.2 + n/-5.53
does this look good so far?
-1398 = 2200 + n/5530 - 2200

  n = 19.89694

Step-by-step explanation:

You can work the problem using decimal numbers. There is no need to convert everything to integers. Trying to do so just gets you in trouble.

Subtract 2.2 from both sides:

  -1.398 -2.200 = n/-5.53

  -3.598 = n/-5.53

Now, multiply both sides by -5.53:

  (-5.53)(-3.598) = n = 19.89694

The one rule that cannot be violated in algebra is that you must do the same thing to both sides of the equation.

Your "solution" so far has a couple of errors. The first is that you have apparently multiplied all of the numbers by 1000. Unfortunately, when you multiply a denominator by 1000, it is the same as dividing by 1000. So, you have multiplied the left side by 1000, multiplied one term on the right by 1000 and divided another term on the right by 1000. This turns the equation into something different than what you started with, and will give a wrong answer.

The second error is that you have subtracted 2200 only from the right side. This, too, will turn the equation into something different than what you started with, and will give a wrong answer.

the answer is 13

step-by-step explanation:

5*5=25

12*12=144

25+144=169

169^2=13