There are a variety of methods of data collection. 2 examples include<span> observations, textual or visual analysis (eg from books or videos) and interviews (individual or group).</span>
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:
D
Step-by-step explanation
A. there are 6 triangles so not this
B. Only 2 rectangles
C. 6 triangles once again
D. everything matches