How do you factor #21m^2 - 57m + 30#?

1 Answer
Nghi N.
Jun 16, 2015

Factor: #y = 21m^2 - 57m + 30#

Explanation:

#y = 3(7m^2 - 19m + 10)#

To factor the trinomial in parentheses, i use the new AC Method (Google, Yahoo Search)
Converted trinomial: #m^2 - 19m + 70.# Roots have same sign. Compose factor pairs of a.c = 70 -> (2, 35)(5, 14). This sum is 19 = -b.
Then, p' = -5 and q' = -14. Next,# p = -5/7# and #q = -14/7 = -2.#

Factored form: #y = 3(7m - 5)(m - 2)#

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