1)
[tex]2x^2-3x+1 > 0\\a = 2\\b = -3\\c = 1\\\Delta = b^2-4ac\\\Delta=(-3)^2-4*2*1\\\Delta = 9-8\\\Delta=1\\[/tex]
2)
[tex]x^2-4x=5\\x^2-4x-5=0\\a=1\\b=-4\\c=-5\\\Delta=(-4)^2-4*1*(-5)\\\Delta=16+20\\\Delta=36[/tex]
3)
[tex]5(x+1)<x(3-x)\\5x+5<3x-x^2\\x^2+5x-3x+5<0\\x^2+2x+5<0\\a=1\\b=2\\c=5\\\Delta=2^2-4*1*5\\\Delta=4-20\\\Delta=-16[/tex]
4)
[tex]-x^2-6x-9=-\\a=-1\\b=-6\\c=-9\\\Delta=(-6)^2-4*(-1)*(-9)\\\Delta=36-36\\\Delta=0[/tex]
