Answer: 
Step-by-step explanation:
Let be "x" the original volume of the solution (in milliliters) before the acid was added and "y" the volume of the solution (in milliliters) after the addition of the acid.
Set up a system of equations:

Applying the Substitution Method, you can substitute the second equation into the first equation and then solve for "x":
Answer: 49 pie
Step-by-step explanation:
<h3>7²</h3>
This is a composite. Another way to write them is f(g(x)). Take the function g(x) and stick it in for x in f(x). Like this:

. But we aren't done cuz there's some simplifying there to do.

and canceling out the 3's we get just a simple x as our answer. The choice is the last one above as your answer.
Answer:
First I need the whole question and second I am guessing around 76 or 72.
Step-by-step explanation:
Answer:
See proof below
Step-by-step explanation:
One way to solve this problem is to "add a zero" to complete the required squares in the expression of xy.
Let
and
with
. Multiplying the two equations with the distributive law and reordering the result with the commutative law, we get 
Now, note that
by the commutativity of rational integers. Add this convenient zero the the previous equation to obtain
, thus xy is the sum of the squares of
.