Factor the gcf: −6m2 + 18m − 36.
−6(m2 − 3m + 6)
−1(6m2 − 18m + 36)
−6m(m2 − 3m + 6)
−6(m2 + 3m − 6)

The first option is the right one.

You have to find the greates common divisor of the coefficientes, which is -6 and then divide each momomial with lead to: -6 (m^2 + -3m + 6).

You can verifiy the result by multiplying -6 times the polynomial inside the parenthesis, using the distributive property.