Answer:
That is not a function :)
Step-by-step explanation:
You can recognize functions by seeing if it passes the <em><u>vertical line test</u></em><em><u>.</u></em> If you draw a vertical line anywhere are the grid and it crosses the equation in more then one place then it does not pass the test, and is not a function.
Here's an attachment that might help
Figure B, it's volume is 48 while figure A is 36
Blue area = big rectangle area - small rectangle area
= 14 x 14 - 8 x 10
= 196 - 80
= 116 cm2
Edit - sorry didnt see the other person already solved the prob in comments :)