Question

brainlist question

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Answer 1

Explanation:

i)

Given equation is x²+kx-21 = 0

Given root = 3

If 3 is the root of the given equation then it satisfies the given equation.

=> (3)²+k(3)-21 = 0

=> 9+3k-21

=> 3k-12 = 0

=> 3k = 12

=> k = 12/3

=> k = 4

Therefore, k = 4

The value of k = 4

ii)

Given equation is x²+kx-5= 0

Given root = 1

If 1 is the root of the given equation then it satisfies the given equation.

=> (1)²+k(1)-5 = 0

=> 1+k-5 = 0

=> k-4 = 0

=> k = 4

Therefore, k = 4

The value of k = 4

iii)

Given equation is x²+12x+k = 0

Given root = -5

If -5 is the root of the given equation then it satisfies the given equation.

=> (-5)²+12(-5)+k= 0

=> 25-60+k = 0

=> -35+k = 0

=> k = 35

Therefore, k = 35

The value of k = 35

Answer:-

i)The value of k = 4

ii)The value of k = 4

iii)The value of k = 35

Used formulae:-

If a number is a root of the given equation then it satisfies the given equation.

Answer 2

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