Factorize 4a+11ab=15b²

What's the difference between: x≥0 and nonnegative integer. ?

Solve the following inequalities and show the solution on a number line. 3/4 (2x-7) ≤ 5

For the chance to be team captain, the numbers 1-30 are put in a hat and you get two chances to pick a number, without replacement. which formula correctly shows how to find the probability that you choose the number 1 and then 2?