Find the value of k for which the roots of the quadratic equation (k-4)x2 +2(k-4) x +2=0.
Answers
Step-by-step explanation:
- the value of k is 7/2 is the answer
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Question:
Find the value of k for which the quadratic equation (k-4)x² + 2(k-4)x + 2 = 0 has equal roots.
Answer:
k = 4 ,6
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 ;
(k-4)x² + 2(k-4)x + 2 = 0
Clearly , we have ;
a = k - 4
b = 2(k-4)
c = 2
We know that ,
The quadratic equation will have equal roots if its discriminant is equal to zero .
=> D = 0
=> [2(k-4)]² - 4•(k-4)•2 = 0
=> 4(k-4)² - 4•2(k+1) = 0
=> 4(k-4)•(k-4-2) = 0
=> (k-4)(k-6) = 0
=> k = 4,6