K Kaatie Member Joined Sep 25, 2007 Messages 452 Gender Female HSC 2009 Nov 9, 2008 #1 find all the possible values of k if one of the roots of x^2 - kx - (k + 1) = 0 is 6 more than the other also find all possible roots

find all the possible values of k if one of the roots of x^2 - kx - (k + 1) = 0 is 6 more than the other also find all possible roots

shaon0 ... Joined Mar 26, 2008 Messages 2,029 Location Guess Gender Male HSC 2009 Nov 9, 2008 #2 Kaatie said: find all the possible values of k if one of the roots of x^2 - kx - (k + 1) = 0 is 6 more than the other also find all possible roots Click to expand... Let roots be; a and a+6 Sum of roots: a+a+6 = k 2a+6=k....1 Product of roots: a(a+6)= -(k+1) a^2 + 6a +k+1=0 .....2 Sub 1 into 2. 2a+6+a^2+6a+1=0 a^2+8a+7=0 (a+7)(a+1)=0 Thus, a= -7 and -1.....3 Sub 3 into 1. 2a+6=k k=-8 or 4.

Kaatie said: find all the possible values of k if one of the roots of x^2 - kx - (k + 1) = 0 is 6 more than the other also find all possible roots Click to expand... Let roots be; a and a+6 Sum of roots: a+a+6 = k 2a+6=k....1 Product of roots: a(a+6)= -(k+1) a^2 + 6a +k+1=0 .....2 Sub 1 into 2. 2a+6+a^2+6a+1=0 a^2+8a+7=0 (a+7)(a+1)=0 Thus, a= -7 and -1.....3 Sub 3 into 1. 2a+6=k k=-8 or 4.

shaon0 ... Joined Mar 26, 2008 Messages 2,029 Location Guess Gender Male HSC 2009 Nov 10, 2008 #4 Kaatie said: thanks alot Click to expand... No worries.