Which number is a solution of the inequality of 6> z(10-z)

For what values of b will f(x)= logbx be a decreasing function? (16 )

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?

If johnny ate 5 cans of sugar, but in the kitchen they only had 3. what did johnny eat? (he found a secret stash btw.)