Question

two zeroes of a cubic polynomial ax³+3x²-bx-6 are -1 &-2 . Find the third zero and value of a and b
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Answer 1

Step-by-step explanation:

let roots be l,m,n(l=-1,m=-2)

lmn=-(-6)/a=2n

n=3/a---------1

l+m+n=-3/a

n=3-3/a---------2

from (1)

2n=3

n=3/2

put value of n in (1),

we get a=2

And,lm+mn+nl=2+(-3)+(-3/2)

=-5/2=-b/a

b=5

therefore,a=2,b=5