How do i solve 3+4x (less than or equal to sign) x-2

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?

Find the zeros of each function. f(x) = 6x^2 - 7x - 20

Which geometric principle is used to justify the construction below?