1、 2018 150 120 6 3 18 1 O 5 P O 7 P O A P O B P O C P O D 2 PA PB O A B P PAB A 5 B 6 C 65 D 7 3 AB O CD O ABD=50 C A 60 B 50 C 40 D 30 4 100 81 x A. 81(1- - 5 A B C D 5 , AB=8, AB 2 . 6 P O OP O Q PQ=OQ P l1 l2 O l1 l2 A 0 30 B 0 45 C 0 60 D 0 90 3 6 2 B A O P 10 3 30 7 x 2 = 2x .8. 2x 2 +4x+1=0 x1,
2、x2, x1+x2+ 2 1 x 3 x . 9 2 10 ABCD O BOD= 11 AB O D AB DC O C D 12 P x A B P 4 2 A 2 0 B 13. , 2 P y=2x 1 P y P 14 ABC AC=6 BC=8 O AC BC BA E D F O r 15 14 E F D O B A C 13 11 10 9 F E D C B O A 12 15. 2cm O AB _ 16. ABCD AB=4 BC=5 AB O BC P O E P 2 - 2 2 DP _. 10 102 17 ( 5 , 10 ) 1 x 2 - 6x+5=0 2
3、16(2x 1) 2 = 25(x 2) 218 8 ) 1 1 ( ) 1 ( 2 2 2 x x x x x x 2 x 3=0 19. 8 1 A B C 1 D AD CD . 3 2 1 D _ . 2 ADC _ . 3 O xy C B A20. 10 25 100 400 1 AB x BC x D C O A B 16 2 AB BC 21. 10 ABC 1 C I I AB BC AC D E F. 2 DE= EF , ABC . 22 10 OABC O OA AB D AO O E CD CE CE O 1 CD O 2 CO O F, CF=2 CD=4 CB C
4、 A B 21 22 23 10 ABC BAC 45,P BC AP O AB AC E F 1 EF 4 2 AP 2 B 60,AB=6 BP EF 24 10 Rt ABC AC=8 AB=10 P AC P A C PC=x P AB y 1 y x (4 ) 2 P x AB x (6 ) 24 E F O C B A P 23 (25 26 ) 120 150 3 6=18 1 2 3 4 5 6 3 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 102 17 ( 5 , 10 ) 1 x 2 - 6x+5=0 2 16(2x 1) 2 = 25(x
5、2) 218 8 ) 1 1 ( ) 1 ( 2 2 2 x x x x x x 2 x 3=0 _ 19. 8 D _ . 2 ADC _ . 3 20. 10 1 AB x BC x 2 AB BC 21. 10 O xy C B A C A B 21 22 10 23 10 24 10 22 E F O C B A P 23 24 25. 12 x k k x 2 2 x =0 ( k ) (1) 4 (2) 01 k n n m m , m n 4 (3) (2) y=x+k y C y A(0,m) B 0 n , k k . 4 26 14 A B O P P A B 1 P O O 1 APB 1 P 2 AB 1 APB 4 2 2 P O PA PB O C D( C A D B ) AD CAD ADB APB 4 3 3 A AM AB AM O C, BC, BC O 2 AB=3 AC=4 D CD=2 E BD D AE . 2 2 C D O P B A 3 O M E C B A D 1 O B A
