Find the value of k for which one root of the quadratic equation kxsq.-14x+8=0 is 2
Answers
kx² - 14 x + 8 = 0
x = 2 because it is one of the root of given quadratic equations.
4 k - 28 + 8 = 0
k = 5
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Question:
Find the value of k for which one of the roots of the quadratic equation kx² - 14x + 8 = 0 is 2 .
Answer:
k = 5
Note:
• An equation of degree 2 is know as quadratic equation .
• Roots of an equation is defined as the possible values of the unknown (variable) for which the equation is satisfied.
• The maximum number of roots of an equation will be equal to its degree.
• A quadratic equation has atmost two roots.
• The general form of a quadratic equation is given as , ax² + bx + c = 0 .
• The discriminant of the quadratic equation is given as , D = b² - 4ac .
• If D = 0 , then the quadratic equation would have real and equal roots .
• If D > 0 , then the quadratic equation would have real and distinct roots .
• If D < 0 , then the quadratic equation would have imaginary roots .
Solution:
The given quadratic equation is ;
kx² - 14x + 8 = 0
According to the question,
One of the roots of the given quadratic equation is 2 , thus x = 2 will satisfy the given quadratic equation.
Thus,
=> kx² - 14x + 8 = 0
=> k•2² - 14•2 + 8 = 0
=> 4k - 28 + 8 = 0
=> 4k - 20 = 0
=> 4k = 20
=> k = 20/4
=> k = 5