1) 4x^2=-4x-1
2) 6x^2-17x+12=0
3)3x^2-7=4x

1) 4x^2=-4x-14x^2+4x+1=0D=16-4*4*1=16-16=0D=0x=-b/2ax=-4/8x=-0,52)6x^2-17x+12=0D=289-4*6*12=289-288=1x1,2=17+-1/12x1=4/3;  x2=1,52)3x^2-7=4x3^2-4x-7=0D=16-4*3*(-7)=16+84=100x1,2=4+-10/6x1=-1;    x2=7/3