Zahra wants the equation below to have an infinite number of solutions when the missing number is placed in the box. Box (x minus 3) + 2 x = negative (x minus 5) + 4

Which number should she place in the box?
–3
–1
1
3

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?