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https://tex.z-dn.net/?f=1)~%5Cboldsymbol%7By%3D%5Cdfrac5%7Bx%5E2%2Bx-2%7D%7D%5C%5C%5C%5CD(y)%3Ax%5E2%2Bx-2%5Cneq%200%5C%5C(x%2B2)(x-1)%5Cneq%200%5C%5Cx%5Cneq%20-2%3B~~~x%5Cneq%201%3B%5C%5C%5C%5C%5Cboldsymbol%7BD(y)%3D(-%5Cinfty%3B-2)%5Ccup(-2%3B1)%5Ccup(1%3B%2B%5Cinfty)%7D