If A = 2 r 2 + 6 r + 1 A=2r 2 +6r+1 and B = 2 r − 6 , B=2r−6, find an expression that equals 2 A − 3 B 2A−3B in standard form.

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.