... DN CHM ẩ THI HK II TON Nm hc 20 12- 2013 Cõu (1,5) Ni dung b c (0 ,25 ); x1.x2 = (0 ,25 ) a a b c b) x1 + x2 = (0 ,25 ); x1.x2 = a a2 im 0,5 a) x1 + x2 = (0 ,25 ) x 12 + x 22 = (x1+x2 )2 2x1x2 = th s = ... bit B1a , B1b 0 ,75 B2a , B2b 0 ,75 B3 0 ,25 HV 0,5 Vn dng B1b 0 ,75 B2c 1,0 B3b 0 ,75 B4b,c 2, 0 HV B5 Thụng hiu B1a 0, B2b 0, 75 B3a 0, B4a 0, B5 0 ,25 0, 25 Tng 2, 5 2, 5 Tng Bi 2, 0 Bi 2, 5 Bi 1,5 Bi ... cú 3im Biu din ỳng v ỳng p Lp lun vit c phng trỡnh 2x2 -20 07x -20 09 = p dng h qu h thc Vi-Et Tim c x1 =-1; x2 = 20 09 /2 Tỡm c y1 = ;y2 =20 0 92 / 2 Kt lun ỳng to giao im Gi x(m) l chiu di ỏm t hỡnh...