For what values of k does the equation x(square) + (k - 2) x + k + 1 = 0 has equal roots.
Answers
If the equation x²+(k-2)X+k+1=0 has equal roots than the discriminant of the equation will be equal to zero.
Also we know that discriminant (D)=
b²-4ac
Which will be equal to zero because the given equation has equal roots.
Therefore b²-4ac=0
Or, (k-2)²-4(1)(k+1)= 0 {since here a= constant of x² which is 1, b=constant of x which is (k-2) and c=last constant term}
Or, {(k)²-2(k)(2)+(2)²}-{4(k+1)}=0
{Since (a-b)²= a²-2ab+b²}
Or, (k²-4k+4)-(4k+4)=0
Or, k²-4k+4-4k-4=0 {by opening brackets}
Or, k²=0
Or, k=√0
Therefore k=0
Therefore the required value of k is 0
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Answer:
Step-by-step explanation:
Given eqution x² + (k-2)x + k+1 = 0
Compare this with ax² + bx + c = 0 , we get
a = 1 , b = k-2 , c = k+1 ,
Discreminant (D) = 0 [ Roots are equal ]
=> b² - 4ac = 0
=> (k-2)² - 4×1×(k+1) = 0
=> k² - 4k + 4 - 4k - 4 = 0
=> k² - 8k = 0
=> k( k - 8) = 0
=> k = 0 Or k - 8 = 0
=> k = 0 Or k = 8
Therefore.,
Value of k = 0 Or k = 8
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