Question

hi frnds i did one sum , find the zeros of x²-2x-8 polynomial and verify is the question. pls see whether my ans is correct or not.

Answer 1

you put wrong value of b b=-2
and hence the sum of two zeroes -b/a
-(-2)/1=2
and in last when you verify by multiplying 4×-2=-8

Answer 2

Let p(x)=x^2-2x-8
To find zeroes we have to take p(x)=0
x^2-2x-8=0
x^2-4x+2x-8=0
x(x-4)+2(x-4)=0
(x-4)(x+2)=0
x-4=0 or x+2=0
Therefore
x=4or x=-2
i) compare p(x)=0 with ax^2+bx+c=0
a=1, b= -2 , c= -8
Sum of the zeroes= 4-2=2
Sum of the zeroes= -b/a= -(-2)/1=2

Product of the zeroes =4*(-2)= -8
Product of the zeroes=c/a
=-8/1=-8