How do you solve system of linear equations

There are 45 questions on your math exam. you answered 810 of them correctly. how many questions did you answer correctly?

Find the vertex for the parabola given by the function ƒ(x) = −3x2 − 6x.

15. jiovanni is looking in to two different companies that offer study guides for math exams.test prep 101 charges a $5 flat fee and an additional $0.25 per problem.math charges a $2 flat fee and an additional $0.50 per problem.how many prablems would make the costs of the two companies be equal? varibles: equations/eniqualities{ {