Grouping common factor: x? (x? + 1)+(x? + 1)= 12; ∴(x? + 1)(x? + 1)= 12
(2). In Equation X? -( 12-m)x+m- 1=0, where a= 1, b=-( 12-m) and c=m- 1, the final product can be obtained by directly applying Vieta's theorem:
x? +x? =-b/a =-[-( 12-m)]/ 1 = 12-m; x? x? = c/a =(m- 1)/ 1 = m- 1。