Question

plz solve q 11 answer not given ​

Answer 1

Answer:

Step-by-step explanation:

x²-1 is a factor of

let f(x)=ax³+bx²+cx+d

hence x²-1 is a factor of f(x)

hence (x-1)(x+1) is factor of

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hence x-1 is factor of f(x)

so f(1)=0

a(1)³+b(1)²+c(1)+d=0

a+b+c+d=0--------(1)

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Also x+1is factor of f(x)

so f(-1)=0

a(-1)³+b(-1)²+c(-1)+d=0

-a+b-c+d=0--------(2)

subtracting (2 ) from (1)

a+b+c+d-(-a+b-c+d)=0

a+b+c+d+a-b+c-d=0

2a+2c=0

2(a+c)=0

a+c=0

hence proved