Question

Suppose a quadratic equation is given as follows:

(k – 1)x² + x + 1 = 0
Select all values of k for which the above equation has two real and unequal roots
0
.25
0.5
0.75
1
1.25
1.5
1.75

Answer 1

k>1.25

Explanation:

The given quadratic equation is :

(k – 1)x² + x + 1 = 0

We need to find all values of k for which the above equation has two real and unequal roots.

For a quadratic equation ax²+bx+c=0, for real and unequal roots,

b²-4ac>0

Here, a = (k-1), b = 1 and c = 1

Put all the values,

1²-4×(k-1)1>0

1-4k+4>0

5-4k>0

k>1.25

S, k can take values more than 1.25. Hence, it can take values 1.5, 1.75.