If 2+2=fish 3+3=8 then what is 7+7=? (hint flip the numbers)

If f(x)= sqrt4x+9+2, which inequality can be used to find the domain of f(x)?

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?

The difference of two numbers is 40. find the numbers if 0.3 parts of one number is equal to 37.5% of the other one.