B BadBoo New Member Joined Aug 16, 2012 Messages 19 Gender Male HSC 2013 Aug 30, 2012 #1 Hey guys, can you please help me with this question: If a and B are the roots of the quadratic equation 2x^2+4x-5=0, evaluate a^3+b^3. Thanks!
Hey guys, can you please help me with this question: If a and B are the roots of the quadratic equation 2x^2+4x-5=0, evaluate a^3+b^3. Thanks!
RealiseNothing what is that?It is Cowpea Joined Jul 10, 2011 Messages 4,591 Location Sydney Gender Male HSC 2013 Aug 30, 2012 #3 Alternative way: Multiply both sides by 'x': Since A and B are roots: Solve simultaneously: Now we want to find Using sums and products of roots: Also note that: Sub this into the other expression we got: Let's hope I didn't typo this time..... Last edited: Aug 30, 2012
Alternative way: Multiply both sides by 'x': Since A and B are roots: Solve simultaneously: Now we want to find Using sums and products of roots: Also note that: Sub this into the other expression we got: Let's hope I didn't typo this time.....
B BadBoo New Member Joined Aug 16, 2012 Messages 19 Gender Male HSC 2013 Aug 30, 2012 #4 Thank you very much!