Find a quadratic polynomial one of whose zeroes is (2 − √3) and sum of the zeroes is 4
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Answer:
x^2 - 4x + 1
Step-by-step explanation:
Since one root is 2 - sqrt(3), the other is 2 + sqrt(3)
[ Proof :
Since sum of the roots is equal to 4:
2 - sqrt(3) + 2 + sqrt (3) = 4 ]
Now , the factors of the polynomial is ( x - ( 2 - sqrt(3)) and ( x - ( 2 + sqrt(3))
To find the resulting polynomial, multiply the 2 factors.
( x - ( 2 - sqrt(3))*( x - ( 2 + sqrt(3))
[ Use the property (x-a)(x-b) = x^2 - (a+b)x + ab
= x^2 - ((2 - sqrt(3)) + ( 2 + sqrt (3)))x + (2 - sqrt(3))(2 + sqrt(3))
= x^2 - 4x + (2^2 - (sqrt(3))^2)
= x^2 - 4x + (4-3)
= x^2 - 4x + 1
Hope you understood my explanation.
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