8.(1)
∵△=√[(√15)²-4×1×(3/2)]=√9=3.
∴x1=(3-√15)/2,或x2=(-3-√15)/2.
.(2)
∵△=√[(-1)²-4×2×(-4)]=√33.
∴x1=(1+√33)/4,或x2=(1-√33)/4.