Answer:
The number is 3.
Step-by-step explanation:
To find : A number which decreased by 12 equals 3 times it’s opposite ?
Solution :
Let the number be 'x'.
It's opposite is '-x'.
A number which decreased by 12 equals 3 times it’s opposite
i.e. 
Solving the equation,





Therefore, the number is 3.
y = ( 3 * x ) - 2.
This is because the card costs for 3 $ and should be multiplied by the number of total cards she buys in that particular day. So 3 * x.
Now as she has got a 2$ off coupon, whatever the total is she gets 2 dollars off on that price. So we will subtract 2 at that time. FInally all this summed up would be equal to y.
Hyperbole is the correct answer