Not enough information im srry :|
Answer and Step-by-step explanation:
If you see a number or fraction or anything we g beside it, such as:
4.2g
6g

^ That is grams
If you see anything with kg next to a number, fraction, e.t.c, such as

5kg
6.2kg
^ That is kilograms
We use letters to substitute for unknown numbers. I hope this helps. :)
9x+ 5y=35
2x + 5y=0 |* -1
9x +5y= 35
-2x -5y= 0
-----------------
7x / = 35
x=35:7
x=5
2x+5y=0
2*5+5y=0
10+5y=0
5y=-10
y= -10:5
y=-2