Mia deposits either $5 or $3.50 into her savings account. she made 14 deposits equaling a total of $59.50.
how many times did she deposit $5 and how many times did she deposit $3.50?
mia made deposits of $5 and deposits of $3.50.

You need to make a system of equations :)
x = number of times she deposited 5 dollars
y = number of times she deposited $3.50
Equation One: 5x + 3.5y = 59.5
Equation Two: x + y = 14
I'm using the substitution method, because I find that to be the fastest. 
For equation two, subtract y from both sides ( (x+y)-y = 14 - y)
You'll get x = 14 - y
Substitute the new equation two in for x in equation one: 
5(14-y) + 3.5y = 59.5
70 - 5y + 3.5y = 59.5
70 - 1.5y = 59.5
-1.5y = -10.5
-1.5y/-1.5 = -10.5/-1.5
y = 7
Plug in y for the original equation two, 
x + 7 = 14
x = 7
Mia deposited $5 seven times and $3.50 seven times.

The correct answer is -20y