--Percent means out of 100, so 20% = 20/100
The prob in other words is asking
-- $60 is 20% of what number?
'$60' -- ---> 60
'is' -- ---> =
20% -- ---> 20/100
'of' -- ---> * (multiply)
'what number' ---> x (variable)
Answer:
The First one is the answer
X-y=3=>x=3+y
X+2y=-6
=========
3+y+2y=-6
3+3y=-6
3y=-6-3
3y=-9
y=-3
X+2y=-6
X+2(-3)=-6
X-6=-6
X=0