Answer:
Identity property of multiplication
Step-by-step explanation:
From step 5:

Here, to solve for x so that the variable x stands alone, Alberto uses the identity property of multiplication, which justifies what he has in step 6.
Step 6:

According to the identity property of multiplication, any value you multiply by 1 gives you that same value.
Therefore, 1x = 1 × x = x.
The variable x multiplied by 1 will give you x.
Judging by the question I generated the equation y=75(1.09^x)
x is the amount of years.
So the equation you should get for 10 years is y=75(1.09^10)
The answer you get should get is $177.55
Y - 4.5 = 12.2
your solving for y which means your trying to get rid of 4.5 so that y can equal something. The opposite of -4.5 would be +4.5, so you would add 4.5 to both sides to get
y = 16.7
So your answer would be
A. Add 4.5
and also dont' say your stupid because all you need is a little explanation and you'll get it, its very easy you just need to take the time to practice :-)