Question

has real roots.
17. Find the value of a for which the equation (a -12)x2 +2 (a - 12)x+2 = 0
has equal roots.
[CBSE 2013)
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Answer 1

Answer:

Given: kx2 + 1-2(k-1)x + x2

sol;

=kx2 + x2 -2(k-1) +1

x2 (k+1) - 2(k-1) +1

here,

a=(k+1) b= -2(k-1) & c= 1

for real and equal roots;

D=0

=b2- 4ac=0

Putting the values of a.b and c

[-2(k-1)]2 - 4 (k+1)(1)=0

then on opening the brackets we'll get;

(4k)(k-3)=0

= 4k=0 and (k-3)=0

= k=0 or k=3

k=3