Factor completely, then place the answer in the proper location on the grid.

21a2-57a + 30

3 (7 a - 5) (a - 2)

Step-by-step explanation:

Factor the following:

21 a^2 - 57 a + 30

Factor 3 out of 21 a^2 - 57 a + 30:

3 (7 a^2 - 19 a + 10)

Factor the quadratic 7 a^2 - 19 a + 10. The coefficient of a^2 is 7 and the constant term is 10. The product of 7 and 10 is 70. The factors of 70 which sum to - 19 are - 5 and - 14. So 7 a^2 - 19 a + 10 = 7 a^2 - 14 a - 5 a + 10 = a (7 a - 5) - 2 (7 a - 5):

3 a (7 a - 5) - 2 (7 a - 5)

Factor 7 a - 5 from a (7 a - 5) - 2 (7 a - 5):

Answer: 3 (7 a - 5) (a - 2)