in a2+px+q, the roots are a and b, then a+b=-p and ab=q why????? Pls derive this!!!!!!!

Question

vikas askiitian expert · Answer

x 2 + px + q = 0 a,b are the roots of this equation so x = a will satisfy this eq at x = a a 2 + pa + q = 0 ..............1 at x = b also satisfies this equation so at x =b b 2 + pb + q = 0 ..............2 subtracting both equations (a 2 -b 2 ) + p(a-b)) = 0 (a-b)[(a+b) + p] = 0 (a+b) = -p ...........3 ans1 adding eq1 & eq2 a 2 +b 2 + p(a+b) + 2q = 0 [(a+b) 2 = a 2 +b 2 + 2ab] (a+b) 2 -2ab + p(a+b) + 2q = 0 from eq3 plugging value of a+b p 2 - 2ab - p 2 + 2q = 0 q = ab ...........4 ans2 hence , a+b = -p & ab = q

Thank you for registering.

Register Now and Win Upto 25% Scholorship for a Full Academic Year !

Enter Your Details

Registration done!

in a2+px+q, the roots are a and b, then a+b=-p and ab=q why????? Pls derive this!!!!!!!

in a2+px+q, the roots are a and b, then a+b=-p and ab=q why????? Pls derive this!!!!!!!

1 Answers

Think You Can Provide A Better Answer ?

Provide a better Answer & Earn Cool Goodies See our forum point policy

Other Related Questions on Magical Mathematics[Interesting Approach]

ASK QUESTION

Answer and earn gift vouchers

View courses by askIITians

Design classes One-on-One in your own way with Top IITians/Medical Professionals

Complete Self Study Package designed by Industry Leading Experts

Live 1-1 coding classes to unleash the Creator in your Child

a Complete All-in-One Study package Fully Loaded inside a Tablet!

Register Now & Win Upto 25% Scholorship