First, you put known numbers apart ( numbers without x ) and unknown numbers apart (numbers with x ), and of course don't forget that when you move a number from a part to another, his sign change, So you get:
Now, you need to have the same denominator so you can add 2/1 and 2/9. So, you multiply 2/1 by 9, so you get:
Then you add the 2 fractions and you get:
Now, you divide each term by 8, so you get:
in
, you removed 8 and 8 and you get x, so you get:
as you know, 8 = 8/1, and when you got a division of 2 fractions, you multiply the first by the inverse of the second, which means you get:
And now you multiply, so you get:
20 and 72 have a common factor, so you divide each by 4, and you get:
So,
Hope this Helps! :D