5t2 + 12t + 7.


By splitting the middle term


5t2 + 12t + 7 = 0


5t2 + (5t + 7t) + 7 = 0


5t2 + 5t + 7t + 7 = 0


5t (t + 1) + 7(t + 1) = 0


(t + 1)(5t + 7) = 0


(t + 1)(5t + 7) = 0


t = - 1. - 7/5


Verification:


Sum of the zeroes = - (coefficient of x) ÷ coefficient of x2


α + β = - b/a


(- 1) + (- 7/5) = - (12)/5


= - 12/5 = - 12/5


Product of the zeroes = constant term ÷ coefficient of x2


α β = c/a


(- 1)(- 7/5) = - 7/5


- 7/5 = - 7/5


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