Question

Which of the following has real roots.

1 x2 + 2V3x - 1 = 0
2 x2 + 2x + 4 = 0
3 x2 - x + 1 = 0
4 3x2 - 2x + 2 = 0​

Answer 1

A is correct answer

Answer 2

Step-by-step explanation:

For finding real roots Discriminate will be greater than equal to zero

so D= b²-4ac

1) x² +2√3x -1 =0

here a= 1, b= 2√3, c= -1

hence D=b²-4ac

= (2√3)² - 4×1×(-1)

= 12 + 4

= 16 which is >0 then it will give real roots.

similarly

2) x² + 2x+ 4= 0

Here

D = -12 which is less than zero hence not real

3) x² - x +1 =0

Here

D = -3 which is less than zero hence not real

4) 3x² - 2x +2 =0

Here

D = -20 which is less than zero hence not real

So only 1 will give real roots...