10-
5-
-10
-5
5
10
-10-
What is the equation

Sorry guys but as you have a small brain

Find and simplify an expression for the area of five rows of x squares with side lengths of x centimeters.

Each person in an it department of 25 people works on at least one of 3 major projects: system security, program implementation, platform development. 10 people work on system security, 13 work on program implementation, and 12 work on platform development. 4 people work on system security and platform development, 5 people work on program implementation and platform development, and 2 people work on all three projects. how many people work on system security and program implementation?