Question

1
15. If two roots of the quadratic equation ax'+bx+c=0, a *are equal in
magnitude but opposite in sign then find value of 'b'*
Your answer
16. If -5 is the root of the quadratic equation 2x2+px-15=0 and p[x2+x]+k=0
has equal roots then find 'k'*
Your answer​

Answer 1

Answer:

⇒  The given quadratic equation is ax  

2

+bx+c=0

⇒  Let two roots be α and β.

⇒  α=−β                     [ Given ]

⇒  α+β−  

a

−b

​  

 

⇒  −β+β=  

a

−−b

​  

 

⇒  0=  

a

−b

​  

 

∴  b=0                            ------- ( 1 )

We have one root negative so,

∴  αβ<0

∴    

a

c

​  

<0

So, here either c or a will be negative.

Means, a and c  will be having opposite sign.  

a>0,c<0 or c>0,a<0 and b=0.

In options we can see option C satisfy all the conditions.

∴  Posibble conditions are a>0,b=0,c<0

HOPE IT HELPS U

PLZ MRK AS BRAINLIAST ANSWER

Step-by-step explanation: