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Question: If 3 is a root of \(x^{2} + kx - 24 = 0\), it is also a root of...

If 3 is a root of x2+kx24=0x^{2} + kx - 24 = 0, it is also a root of

A

x2+5x+k=0x^{2} + 5x + k = 0

B

x25x+k=0x^{2} - 5x + k = 0

C

x2kx+6=0x^{2} - kx + 6 = 0

D

x2+kx+24=0x^{2} + kx + 24 = 0

Answer

x2kx+6=0x^{2} - kx + 6 = 0

Explanation

Solution

Equation x2+kx24=0x^{2} + kx - 24 = 0 has one root as 3,

32+3k24=03^{2} + 3k - 24 = 0k=5k = 5

Put x=3x = 3 and k=5k = 5 in option

Only (3) gives the correct answer i.e. ⇒ 3215+9=03^{2} - 15 + 9 = 0

0=00 = 0