Which equation demonstrates the multiplicative identity property?
o (-3+51)+1=-3+51
o
(-3+5)(1)=-3+5;
o (-3++5) = -16-30;
o (-3+5)(3-5) = 16+30;

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?