Can someone please do these questions for me

1. what are the missing reasons in the proof 2. it's in the second picture and 3

Simplify 15(x - 4)(x -1)-3(x + 4)(x - 1) with steps

Afrequency table of grades has five classes (a, b, c, d, f) with frequencies of 3, 13, 14, 5, and 3 respectively. using percentages, what are the relative frequencies of the five classes?