Simplify the expressions.
1. 6 + 2b - 3 - 10b
2. 5v – 3v
3. 3t + 10 + 3 - 9t
4. Z + (-32) + 2 + 2
5. K - (-7)k
6. -2a + 10a + 3 - 2a

The pyraminx is a rubik's cube-type toy in the shape of a tetrahedron. the pyraminx shown below has edges 15\,\text{cm}15cm long and vertical height h=12.2\,\text{cm}h=12.2cm. the triangle drawn with dashed lines is a right triangle. what is the distance rr? round your answer to the nearest tenth.