Which function in vertex form is equivalent to f(x) = x2 + 6x + 3?

f(x) = (x + 3)2 + 3
f(x) = (x + 3)2 − 6
f(x) = (x + 6)2 + 3
f(x) = (x + 6)2 − 6

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?