If one of the roots of quadratic equation 7y2

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If one of the roots of quadratic equation 7y² - 50y + k = 0 is 7, then what is the value of k ?

1. 7
2. 1
3. 50/7
4. 7/50

Correct Option: A

Given quadratic equation is
7y² - 50y + k = 0
If one root is 7, then it will satisfy the equation i.e putting y = 7 in equation
7 x (7)² - 50 x 7 + k = 0
⇒ 7 x 49 - 350 + k = 0
⇒ 343 - 350 + k = 0
∴ k = 7