Quadratic equation and nature of roots

What can you say about the roots of the following quadratic equation?
[math]x^2+4x+6=0[/math]
[math]x^2+4x+4=0[/math]
[math]x^2+4x-5=0[/math]
[math]x^2+4x-2=0[/math]
Can you construct a quadratic equation with integral coefficient whose roots are irrational and repeated?
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