Someone please help me with all this

In trapezoid abcd, ac is a diagonal and ∠abc≅∠acd. find ac if the lengths of the bases bc and ad are 12m and 27m respectively.

Find the perimeter of the triangle with vertices  d(3, 4),  e(8, 7), and  f(5, 9). do not round before calculating the perimeter. after calculating the perimeter, round your answer to the nearest tenth.  

Ze trinomial x2 + bx – c has factors of (x + m)(x – n), where m, n, and b are positive. what is ze relationship between the values of m and n? explain how you got ze answer