we have two pairs of answers :
1st pair : j=(5+sqrt(17))/4 & k=(5-sqrt(17))/4
2nd pair : j=(5-sqrt(17))/4 & k=(5+sqrt(17))/4
If you look carefully , both of the answers are merely the same , they inly switched between the - and + .
For the first and second pairs , you will get only one answer for (j-1)(1-k) , which is 1