quadratic

If the roots of the equation x2+ax+b=0 are c and d, then one of the roots of the equation x2+(2c+a)x+c2+ac+b=0 is ???

a)0
b)-2c-a
c)d-c
d)None of these

13 Answers

62
Lokesh Verma ·

x2+(2c+a)x+c2+ac+b

= x2+ax+b+2cx+ac+c2

=(x-c)(x-d)+c(2x+a+c)

a=-d-c

=(x-c)(x-d)+c(2x-d)
=(x-c)(x-d)+c(2x-d)

putting x=0 we get zero
x=d-c gives

(d-2c)(-c)+c(d-2c) which is again zero..

last option -2c-a = -2c+d+c =d-c which is same as the 3rd option..

So a, b, c

11
Subash ·

bhaiyya really sorry

there was a mistake in the question sorry for wasting ur time

ive edited it now

1
big looser ......... ·

fir to answer abc ayga

11
Subash ·

sorry aman take a look at the changed question

62
Lokesh Verma ·

check the changed solution now :)

1
big looser ......... ·

wats the answer

1
big looser ......... ·

its an identity ????

62
Lokesh Verma ·

no aman.. identity means zero for all values of x..

this is zero for only 2 values of x.!

1
big looser ......... ·

oh sorry option b and c are same

11
Subash ·

yes the answer is a,b,c

but there is a better way of looking at the second equation

it is f(x+c)=0

since roots of f(x)=0 are c and d

the roots of f(x+c)=0 should be 0 and d-c

21
tapanmast Vora ·

SIR,
I got ur way of solving.... nice one....

par agar woh strike nahi hota hai to can u tell me if the fol approach of mine wud hav led to any imp conclusion or not....

aage i know it seems bleak...[2]

11
Subash ·

tapan did u see what i posted
i think that would be the shortest method available

62
Lokesh Verma ·

good work subash

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