So basically... you divide the 3 to 2 and that's how you get the decimal. The decimal is... 0.666666666667
The LCD is 10 because you can multiply 2/5 by 2 to get 4/10
Don’t know if there’s much of an equation for it, but I guess the best way to write it out is 10 + x = -18. Then, you would subtract the 10 from both sides in order to isolate the x. So then you’re left with x = -28. So -28 is your answer.
Answer:

Step-by-step explanation:
So we have the expression:

To simplify, simply combine the like terms. Therefore:

Further notes:
To understand why we can combine like terms in the first place, we just need to use the distributive property. So we have the expression:

Now, factor out a y from the three terms:

Do all the operations inside the parenthesis:

And we moved the y back to the front!
This is the same result as before. When combining like terms, this is what we're essentially doing but without doing the distributive property manually. I hope you understand a bit better on how and why we can combine like terms!