FIND the value of a if x+1/2 is a factor of p(x) = 8x^3 - ax^2- x +2
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Answer:
f(x)=x^3-ax^2+bx-8.
(x-1) and (x-2) are the factors of f(x)
On putting x=1 and x=2 .
R=f(1)= 1-a+b-8=0 or -a+b =7……(1)
R=f(2)=8–4a+2b-8=0
-4a+2b=0 or b=2a………….(2)
On putting b=2a in eq.(1)
-a+2a =7 => a=7
b=2a=2×7 =14.
a =7 , b= 14 , Answer.
Answered by
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f(x)=x^3-ax^2+bx-8.
(x-1) and (x-2) are the factors of f(x)
On putting x=1 and x=2 .
R=f(1)= 1-a+b-8=0 or -a+b =7……(1)
R=f(2)=8–4a+2b-8=0
-4a+2b=0 or b=2a………….(2)
On putting b=2a in eq.(1)
-a+2a =7 => a=7
b=2a=2×7 =14.
a =7 , b= 14 , Answer.
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