Which of the following is equivalent to the formula =c2+c3+c4+c7?
=sum(c2: c7)
=sum(c2,c4: c7)
=sum(c2, c3, c4: c7)
=sum(c2: c4, c7)

What is this inequality notation? t is less then or equal to 2

Evaluate the discriminant of each equation. tell how many solutions each equation has and whether the solutions are real or imaginary. x^2 - 4x - 5 = 0

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?