4x**2-2x-0.75=0

D=4+4(4*0.75)=4+12=16

x1=(2+4)/8=3/4=0.75

x2=(2-4)/8=-1/4=-0.25

4x^2 - 2x - 3/4 = 0

16x^2 - 8x -3 = 0

D = 64 + 192 = 256

x₁=(8+16)/(2*16) = 3/4

x₂=(8-16)/(2*16) = -1/4