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If one root of $x^{2} - 7 x + k = 0$ is 3, find the value of $k$ .

Class 10Solving by FactorisationQuadratic Equations

A12
B24
C11
D13

Step-by-Step Solution

Substitute

x = 3 : 9 - 21 + k = 0

, so

k = 12

. (Then the equation factors as

(x - 3) (x - 4) .

)

Answer: A) 12

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