Question

If 4 is a root of quadratic equation x²+ax–8=0, then a = .....,select a proper option (a), (b), (c) or (d) from given options so that the statement becomes correct.
(a) 2
(b) 4
(c) -2
(d) -4

Answer 1

(c)-2 is the correct answer.

Answer 2

Option ( c ) is correct.

Explanation :

Given

Quadratic equation is x² + ax - 8 = 0

and 4 is one root.

put x = 4 in the equation , we get

4² + a × 4 - 8 = 0

=> 16 + 4a - 8 = 0

=> 8 + 4a = 0

=> 4a = -8

=> a = (-8)/4

=> a = -2

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