de thi hsg toan 9 nam 2018 2019 phong gddt thanh pho thai nguyen

UBND THANH PH6 THAI NGUYEN THI CHQN HQC SINH GIOI LO? NAU ng c zotr - zote MON THI: TOAN PHO@T4O DE THI CHINH THTIC bdi: 150 philt, khdng ke thdi gian giao tt€ (Ed tUi g6m c6 01 trang) Thdi gian ldm Bni 1(6 tli6m) a Tinh gi|tri cria bi6u thric A = (x4 - xt - x2 +2x- 1)20te v6i lt-lt-' VV2+1-t r/V2+l+t b Tim m dA dudng thing song song v6i ! =2x+ vd ducrng thang y - (nt' -2m+2)x +2m-L Bhi2 (a di6m) a Chirng minh rdng v6i moi s6 nguyOn duong n thi s6 chinh phucrng b Giai phuong trinh x +qJx+3 *2J3-2-y n(n+2) kh6ng phni ld sd =tt Bni (2 tli6m) Hai b4n An vd Binh choi cd vua vdi Trong m5i v6n, ngudi thing duqc 2- ditlm, nguoi thua duoc di6m vd n6u hda thi m5i nguoid,rq die; H6i sai mQt sd v6n thi d6u, c6 th6 x6y trubng hqp b4n An duoc tOti6m vd b4n Binh dugc 15 di6m duoc kh6ng? T4i sao? Bni (a tli6m) Cho ducrng tron (O) duong kinh AB vd di6m M nim chinh gita cria cung ,48 L6y diom C nim trcn dulng trdn (o) cho C * A,C * B, AC