If alpha and beta are zeroes of polynomial x2-5x+k such that alpha-beta=1.find k
Answers
Step-by-step explanation:
a=alpha
b=beta
p(x)=x^2-5x+k
so,
a-b=1----------(1)
a+b=5---------(2)
Now we will solve,
a-b=1
a+b=5 (-b+b will be cut)
----------
2a=6
----------
so,
2a=6
a=3
to find b,take eqn (1)
a-b=1
3-b=1
-b=1-3
-b=-2 (minus and minus will be cut)
b=2
.:k=ab(alpha × beta)
k=3×2
k=6
k=6 is the answer
here , a=1,b=-5,c=k
α+β= -b/a
= -(-5/1)
= 5/1
= 5
α*β= c/a
= k/1
= k
now, α-β= 1
squaring both the sides, we get,
(α-β)²= (1)²
α²+β²-2αβ = 1
(α²+β²+2αβ)-4αβ= 1
(α+β)²-4αβ = 1
(5)²-4k= 1
25-4k =1
-4k=1-25
-4k= -24
k= -24/-4
k= 24/4
k = 6 (answer)
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