1、 2018 120 150 1 x 2 2 2 2 2 11 3( 1) 2( 1) 2 0 0 2 1 A x x B C ax bx c D x x x y x X2 x 2 8x 1=0 A x+4 2 =17 B x+4 2 =15 C x 4 2 =17 D x 4 2 =15 3 x a+1 x 2 +x+a 2 1=0 0 a A 1 B 1 C 1 1 D 4 A 3 B a A 2 A a 5 B A B 1 a 5 B A C a 1 B A D a 5 B A 5 AB O D= A B C D 6 x 2 +4x+a=0 A 4 a B a 4 C a+4 D 7 x
2、kx 2 2x 1=0 k A k 1 B k 1 k 0 C k 1 D k 1 8 O AC OB OAB A B C D 9 P O PA PB O C D P= A B C 2 D P O B A10 35 20 600 x 11 x 2 =x 12 x kx 2 2x 1=0 k 13 a 2 +b 2 a 2 +b 2 2 =3 a 2 +b 2 = 14 2cm O AB _cm 15 ABC 16 O 10 AB 8 P AB OP _ 17 QQ 90 QQ x 18 a b=a 2 b 2 4 3 x=24 19 AB O AB=10 C O M N AB BC MN 20
3、 2 0 ax bx c 1 x 2 x 12 b xx a 12 c xx a 1 x 2 x 2 6 3 0 xx 21 12 xx xx _ 2017 21 2x 2 4x+1=0 x 2 2x= x 1 2 = x 1= x1=1+ x2=1 2 x x+4 = 5 x+4 x+4 x+5 =0 x+4=0 x+5=0 x1= 4 x2= 5 3 3y 2= 2y 3 y1= 1 y2=1 2x 1 2x 1+3 =0 2x 1=0 2x 1+3=0 4 2x 1 2 +3 2x 1 =0 x1= x2= 1 22 x 2 4x+k=0 1 k 2 k x 2 4x+k=0 x 2 +
4、mx 1=0 m x 2 4x+k=0 =b 2 4ac= 4 2 4k 0 k 4 2 k x 2 4x+k=0 x 2 4x+3=0 x1=1 x 2=3 x 2 4x+k=0 x 2 +mx 1=0 x=1 x=1 x 2 +mx 1=0 1+m 1=0 m=0 x=3 x=3 x 2 +mx 1=0 9+3m 1=0 m= k x 2 4x+k=0 x 2 +mx 1=0 23 OA O OD AB AB=8 AD= AB=4 OA=5 OD= =3 =OA+OD=5+3=8 16 = =0.5 / 24 1 C O BD CO BD O BO=DO O BD CO= BD CO=DO
5、 C O 2 AD=6 AB=8 BD= =10 DO=5 2 25 10 ABCD O E AC EC=BC=DC 1 BAD 2 1= 2 25 1 BC=DC CBD= BAC= CAD= BAD= BAC+ + 2 EC=BC CEB= CBE CEB= 2+ BAE CBE= 1+ CBD 2+ BAE= 1+ CBD BAE= BDC= CBD 1= 2 26 1 a=3 b=4 c=5 3x 2 +5 x+4=0 2 = c 2 4ab=2c 2 4ab a 2 +b 2 =c 2 2c 2 4ab=2 a 2 +b 2 4ab=2 a b 2 0 0 3 x= 1 a c+b=
6、0 a+b= c 2a+2b+ c=6 2 a+b + c=6 3 c=6 c=2 a 2 +b 2 =c 2 =4 a+b=2 a+b 2 =a 2 +b 2 +2ab ab=2 S ABC= ab=1 27 1 20% 2 1 x 2 1+x 2 =2.88 x1 =0.2=20% x2 = 2.2 20% 2 2017 2017 2.88 1+20% =3.456 3 456 3.4 2017 3.4 28 1 P PE CD E x P Q 10cm 16 2x 3x 2+62=102 16 5x 2=64 16 5x= 8 x1= x2= s sP Q 10cm 2 BQ ys PBQ 12cm2 0 y PB=16 3y 16 3y 6=12 y=4 x BP=3y AB=3y 16 QC=2y 3y 16 2y=12 y1=6 y2= x 8 QP=CQ PQ=22 y 22 y 6=12 y=18 4 6 PBQ 12cm 2
