What are the foci of the ellipse given by the equation 25x^2+16y^2=400

If your teacher tells you to do questions 6 through 19 in your math book for homework, how many questions is that

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?

Drag the tiles to the correct boxes to complete the pairs. label each function. as even , odd, or neither.