Using number and symbols solve, 7x = 42

Linda loans her friend $250 with a 5% monthly intrest rate. how much was the whole loan?

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.

Me because i don't understand how to do it.: )