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If one root of $x^{2} - 8 x + k = 0$ is 3, find the other root using the formula and the value of $k$ .

Class 10The Quadratic FormulaQuadratic Equations

Aother root 5, k = 15
Bother root 5, k = 24
Cother root 11, k = 15
Dother root 2, k = 6

Step-by-Step Solution

If 3 is a root,

9 - 24 + k = 0 \Rightarrow k = 15

. Then

x^{2} - 8 x + 15 = 0 \Rightarrow x = \frac{8 \pm 64 - 60}{2} = \frac{8 \pm 2}{2} = 5

or 3. Other root 5.

Answer: A) other root 5, k = 15

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