Question 256185
We start with
(i) {{{b^2 = 13b - 12}}}
setting all = 0, we get
(ii) {{{b^2 - 13b + 12 = 0}}}
factored we get
(iii) {{{(b-12)(b-1)=0}}}
Now we solve to get
b = 12 
or
b = 1