The answer is c.
(a)
x * 2 = y
2 * 2 = 4
3 * 2 = 6
4 * 2 = 8 not 9
(b)
unknown formula
(c)
x * 3 = y
4 * 3 = 12
5 * 3 = 15
6 * 3 = 18
(d)
x * 4
1 * 4 = 4
2 * 4 = 8
3 * 3 = 9 not 15
11 is the biggest and the 22
I don't know if this is the right one but i hope this helps. this is how i learned it.
step 1=get variables on one side oof the equal sign by using inverse operation (add or subtract smaller variable)
step 2= get constants away from variable to the other side of the equal sign by using inverse operations (add or subtract constant)
step 3: isolate the variable using inverse operation (multiply or divide)
Answer:
the atoms can have different numbers of valence electrons