9×2 =18= 2 packs 9×4=36=4 packs 9×5=45=5packs greatest number is 9
Twice means two times something so2a. Four more than means adding for so your answer is 2a+4
-5-(15y-1) = 2(7y-16) - y // question
-5-15y+1 = 14y-32-y // distribute
-15y - 4 = 13y - 32 // subtract
-28y = -28 // divide
y = 1
Changing 
"inverts" the orientation of the x axis, so the graph of f(x) is transformed by reflecting it about the y axis.
Answer
Notebook each =$4
Folder each = $9
First we write out what we know
Notebook = n
Folder = f
It says a notebook is +5 than a folder so
f = n +5
It says he bought 3 notebooks and 2 folders for $30
3n + 2f = 30
Because we know from the first equation
f=n+5, we can substitute that into the second equation for f
3n + 2(n+5) = 30
3n + 2n +10 =30. Now Combine like terms
5n +10 =30. Now isolate n by subtracting 10 from both sides
5n = 20. Now isolate n by dividing both sides by 5
n = 4
Now we do the same thing to find f
We substitute the value of n (4) into the equation 3n + 2f =30
3(4) +2f =30
12 +2f =30. Now isolate f by subtracting 12 from both sides
2f = 18. Now isolate f by dividing both sides by 2
f = 9
We check our work by inserting the n and f values we found into one of the equations
n + 5 = f
4 + 5 = 9
9 = 9. It worked it equals so it’s correct
