(a+1)(a+2)(a+3)(a+4) ={(a+1)(a+4)}{a+2)(a+3)} =(a^2+5a+4)(a^2+5a+6) Let a^2+5a=R (R+4)(R+6) =R^2+10R+24 As per question R^2+11R+24=0 R^2+8R+3R+24=0 R(R+8)+3(R+8)=0 (R+8)(R+3)=0 R=-8 or -3 a^2+5a=-8 a^2+5a+8=0 a= {(-5±*(25-32)}/10....not accepted Again R= -3 a^2+5a+3=0 a={-5±*(25-12)}/10 a={(-5)±*13)}/10, may be *= read as square root
Lcm missed our a+5 though it didn't matter at the end
This problem doesn't even deserve to be a part of Olympiad
(a+1)(a+2)(a+3)(a+4)
={(a+1)(a+4)}{a+2)(a+3)}
=(a^2+5a+4)(a^2+5a+6)
Let a^2+5a=R
(R+4)(R+6)
=R^2+10R+24
As per question
R^2+11R+24=0
R^2+8R+3R+24=0
R(R+8)+3(R+8)=0
(R+8)(R+3)=0
R=-8 or -3
a^2+5a=-8
a^2+5a+8=0
a= {(-5±*(25-32)}/10....not accepted
Again
R= -3
a^2+5a+3=0
a={-5±*(25-12)}/10
a={(-5)±*13)}/10, may be
*= read as square root
Wrong