(2x-5)ˇ2-36=0
4xˇ2-20x+25-36=0
4xˇ2-20x-11=0, D=400+176=576,V(D)=V(576)=24
x1=1/8(20+24)=1/8.44=11/2
x2=1/8(20-24)=1/8.(-4)=-1/2
(5z-3)ˇ2-9zˇ2=0
25zˇ2-30z+9-9zˇ2=0
16zˇ2-30z+9=0, D=900-576=324,V(D)=V(324)=18
z1=1/32(30+18)=1/32.48=3/2
z2=1/32(30-18)=1/32.12=3/8