Latest CAT Aptitude Question SOLUTION: find value 0f x x^2+x-(a+2)(a+1)=0

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(#M40019758) CAT question Keep an EYE

find value 0f x
x^2+x-(a+2)(a+1)=0

Asked In CAT Nitish Kumar (10 years ago)

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k a n v v v prasad  (10 years ago)

Answer is x=a+1;
x^2+x=(a+2)(a+1)
x(x+1)=(a+2)(a+1)
x=a+1 ; x+1=a+2
Eg:
if a=1,then x=2,
4+2-6=0
0=0;

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Md Intshamuddin  (10 years ago)

x^2+x-(a+2)(a+1)=0
=> x^2+[(a+2)-(a+1)]*x-(a+2)(a+1)=0
=> x^2+(a+2)x-(a+1)x-(a+2)(a+1)=0
=> x[x+(a+2)]-(a+1)[x+(a+2)]=0
=> [x-(a+1)][x+(a+2)]=0
=> [x-(a+1)]=0 and [x+(a+2)]=0
hence x=a+1 and x=-(a+2)
and both the roots satisfy the given equation x^2+x-(a+2)(a+1)=0
so there will be two roots of x namely (a+1) and -(a+2).

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ABHISHEK KUMAR MISHRA  (10 years ago)

x^2 + x - (a+2)(a+1) = 0
if we have ax^2 + bx + c = 0
then we can apply x = [-b +(or)- (b^2-4a*c)^1/2]/2a
so x = [-1 +(or)- {(2a+1)(2a+5)}]1/2 /2

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Surya Kiran  (10 years ago)

Given x^2+x-(a+2)(a+1)=0
>>>quadratic roots formula
-b(+/-)sqrt(b^2-4ac)/2a

>>>-1(+/-) sqrt(1-4(1)(-(a^2+3a+2)))/2
>>>-1(+/-) sqrt(4a^2+12a+9)/2
>>>-1(+/-) sqrt(2a+3)^2/2
>>>-1(+/-) 2a+3/2...by solving

>>>>x=a+1 0r x=-(a+2).

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