Help please the picture is attatched

Add the two expressions 3.8b - 7 and 2.9b + 9 enter your answer in simplified form

What is the first step of an indirect proof of a number that is divisible by two

Which is a true statement about an exterior angle of a triangle a. it is formed by two segments that are not sides of the triangle, b. it forms a linear pair with one of the interior angles of the triangle, c. it is complementary to one of the interior angles of the triangle. d. it is formed by two segments that are sides of the triangle.