Confused with these distributive property problems. i am asked to verify the distributive property in them but i dont get why one number is used twice for example;
6 × (2 + 10)
6 × 2 + 6 × 10 < --here in this part why is the 6 used twice after applying the distributive property? and why do you have to multiply by it afterwards?

Find the value of a. the diagram is not to scale. a quadrilateral is drawn. the upper and lower sides are parallel. the interior angle in the upper left corner is labeled a degrees. the angle in the upper right corner is labeled 113 degrees. the angle in the lower right corner is labeled b degrees. the angle in the lower left corner is labeled 36 degrees. a. 36 b. 144 c. 54 d. 126

The sum of two numbers is 86, and their difference is 20. find the two numbers

What is the area of a triangle with vertices at (-3 3) (-3,2) and (1,2)?