Find the length bc rounded to 1 decimal place

Marcus needs to rewrite f(x) = x2 + 6x + 4 in vertex form.

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?

What is the value of x in the equation7x+2y=48 when y=3