Using the splitting middle term - the middle term of the general equation is divided in two such values that:

Product = a.c

For the given equation a = 1; b = -18; c = 77

= 1.77 = 77

And either of their sum or difference = b

= - 18

Thus the two terms are - 7 and - 11

Sum = - 7 - 11 = - 18

Product = - 7. - 11 = 77

x(x-7)-11(x-7) = 0

(x-7)(x-11) = 0

(x-7) = 0 or (x-11) = 0

x = 7 or x = 11

Roots of equation are 7, 11