There are 7 days in 1 week. how many days are there in 10 weeks

What is the solution to the system of the equations? x = y - 3 x + 3y = 13

Which of the following correctly justifies statement four of the two column proof? a. corresponding angles theorem b. transitive property of equality c. vertical angle theorem d. substitution property of equality

Plzzz answer both questions and i will give you 100 points