1-GT12 *** CAu I: A CAu2: ' I!! x+2 Phuong trinh ti6p tuy6n cria ao tni nam s6 y = tai A(-l; 3) c6 hQ s5 g6c li: D Gi6 sri }I : ,f{x} c6 d4o him c6p hai khoirng (xe-h;xe+h), v6i h>0, Khi d6 ntiu f'{xo} : 0,f"{xo) > t} B -1 thi: A C CAu3: y: A Hdm s5 d,5ng bi6n t6n R B Hdm s6 nghich bi6n tr6n kho6ng Him s6 nghich biiSn tr€n R C D C&u4: B D h di6m kir6ng phdi ld diiSm csc ti6u xomQt di,3m cUc dai xo Phat bitiu ndo sau dAy tlung Cho xo xo li [-*; 0) va d6ng bi6n tr6n khoing (0; *m) {-*;0} Hdm s6 ddng biiin tr6n khoing tti6m cFc tiiiu di6m cgc ti6u vd cgc d4i xo mOt vA nghich biiin tr6n khodng (0; *m} f(r) = x3 -rnx2 -x+m citnlc hodnhtai di6m phdn biQt C m0 Nriuf'{x} } 0tren}*ro6ng (ro -Iuxo}vaf'{x.} { Otrenkhoang {ro;xq * h}ttri A xom0t tlii5m cyc tii5u cua him 16 ,f{x} B xo ld mOt di6m qrc dai cria him f{t} C xold m$t tli6m kh6ng phni h tli6m cuc del cua him s6 f{:r} D xold mOt tlirim cyc ct6i vd cpc ti6u cua Ue f{x} Cnu 43 : Tim tdt ci c6c gi6 fi cin m AC mm sO /(x) = x' +mx ttdng biiln n€n t0p x6c dinh cua n6 A m>0 B m>0 c m