Hey can someone tutor me on math till 12? or till i finsh

How do i multiply two digit numbers

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.

If f(x)= x^2 - 4 and g(x)=x^2 + 2 x, (b). (f-g)(x) i think i know the 1st 2 steps: f(x)-g(x) x^2-4 - x^2+2x