1、 A 1-10 DBCCABACAD 11 3 2 x +9x+13=0 12 1 13 2 1 m 14 1 ) 6 ( 2 x y 15 16. 1 1 x =-3 2 x =-5 2 1 x = 6 61 1 - 2 x = 6 61 - 1 -17 1 x 4x 2 = x1= x2= 2 1 850+1575=2425 2425 18 1 1B1 2 2B2 3 19 1 A 2 ABDF AF=2 DF=2 2 20 1 1 10 2 CO CD BO 5 2 1 CD CA x CO 1 x AO Rt CAO 90 CAO 2 2 2 CO CA AO 2 2 2 5 1 x
2、x 13 x O 26 21 1 2 CO = 22 1 S= x 40 10x+1200 = 10x 2 +1600x 48000 2 S= 10x 2 +1600x 48000= 10 x 80 2 +16000 S= 10 x 80 2 +16000 s x x 76 s 15840 23 1 y=x 2 +bx+c x A 2 0 B 6 0 x 2 +bx+c=0 x= 2 x=6 2+6= b 4 c= 12 y=x 2 4x 12 2 2 4x 12= x 2 2 16 x=2 2 16 3 P |yP| =32 P|=32 =6+2=8 P|=8 P yP=8 8=x 2 4x 12 yP= 8 8=x 2 4x 12 P y 2 P 2+2 8 2+2 8
