Can somebody please help me

In the pendulum formula t=2pi. read the problem on the picture ! ; $; $; ! ; ! ; ! ; )$; ! ; ! ; ! ; $; $; $! ; ! ; ); $; $$

Brady has a 20 year fixed rate mortgage for $215,500 with monthly payments of 1,305.89.the annual interest rate is 4%. what is the total cost of the principal and interest for this loan rounded to the nearest dollar

Which expression is equivalent to (4 +6i)^2? ? -20 + 48i 8 + 12i 16 - 36i 20 + 48i