Py+7=6y+q
what is the answer for this question (linear equations with unknown coefficients)?

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?

To decrease an amount by 16% what single multiplier would you use

Write as a product: ac^2–ad+c^3–cd–bc^2+bd