Which of the following is not a solution to the system of linear equations below?

How can you find the conditional probability of a given b as the fraction of b’s outcomes that also belong to a, and interpret the answer in terms of the model? i just need a good explanation

Evaluate the expression for the given value of the variable. 5×(h+3) for h=7

Find the greatest common factor of the followig monomials 21u^5v,3u^4v^6, and 3u^2v^5