HCF of x^2+x-(2a+2)and bx^2+ax-12 is (x+4), Value of b is

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24 Apr 2013 HCF HCF of x^2+x-(2a+2)and bx^2+ax-12 is (x+4), Value of b is: OPtion
1) 1
2) 2
3) 3
4) 4
5) 5
6) 6
7) 7
8) 8
9) 9
10) None of these; Correct Option: 2 Best Solution (3)

krishnapriya 11 years AGO

let p(x)=x^2+x-(2a+2) and q(x)=bx^2+ax-12
given (x+4) is a factor of p(x) and q(x)
then by factor theorem, p(-4)=0 and q(-4)=0
p(-4)=(-4)^2+(-4)-(2a+2)=0
10-2a=0
therefore, a=5

q(-4)=b(-4)^2+a(-4)-12=0
16b-4a-12=0
16b-32=0 (put a=5)
therefore, b=2

Like? Yes (3) | No (1)

ajitha 11 years AGO

By putting x=-4 in both eqns
x^2+x-(2a+2) become 16-4-2a-2=0 then a=5
similarly bx^2+ax-12 become 16b-4a-12=0
by putting a value here b=2
Hence b=2

Like? Yes (1) | No (1)

Mohit Agarwal 11 years AGO

x=-4
find a den find b

Like? Yes (1) | No (1)

Dimple

India

Punjab

Time: 00:01:33

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HCF of x^2+x-(2a+2)and bx^2+ax-12 is (x+4), Value of b is

M4maths Previous Puzzles

24 Apr 2013 HCF