so GIAO DUC vA EAo HAN I rAo Ki Tr{r ruyEN srNH vAo Ldp t0 THpr NAM oAp AN - THANc DIEM Mdn itt rDap Irii \' thi: TOAN Thungt Jietn gom [)-! rrattgt NQi dung Tinh gi6 l) Thay z : tri cta +(.6 bi6u thri'c A = 2) + r) 0,5 khi:r=9 _t: n I - 15t25 tl-G*z( 6*s 0,25 "t va r>o.t *2b I fVr+5 I Vz-5 1,0 i) 0.25 (.'t.s)(.,6-s) l) J"-s t_tV.r-5 )\ 25-9 Rrit gqn bi6u thri'c B 15- "'6 t: -25 /) - Di6m 6*r vdo bi6u thuc ,4 = Tinh duoc ,4 = BNi I 2,0 diam 2019 n )\ n )\ n 15 r Vr-5 V.r+I ( D1 Vr+1 3) T im tat c1i girl nguy 6n k?n nhAt P=A,B= tri +(G.r) 25-t' nguyOn cfra r d bi u 1.4 ".f,*r thric P = ,4.8 dat gi6 tri 0,5 n 25-r I-ap lu{n d0 p dat giii n'i nguy6n lon nhAt bang :r: 2.1 llai ddi c6ng nhin ctng lhm chung rnQt cdng vifc thi sau 1l nghl'lirm xong N5u dQi thri'nh6t tirm ri6ng ;l ngav r6i dnng 14i vir d6i thrir hai lirm ti6p c6ng viQc d6 nghy thi cri hai tlQi hohn thAnh dw1c 25%: cdng viQc Htii n6u m6i a6i lhm ri6ng thi bao nhi6u nghy m6i rong c6ng viQc tr6n ? 2.5 cli€nt 0,2 2,0 li ; ia* ii' ;8ir .; ; aii o:25 Goi thoi gian ddi thu hai ldm ri6ng xong c6ng vi6c ld y (d 0) o )5 cqi ihoi gian doi tnu nhdt ti,r, rieng xong.ong Bii II )\ "ie 1) I ngAy dQi rhu nhdt l2rm duoc I ngal dQi thu hai lirm dutvc ] :t I tcong uiect n )1 (c6ng viec) v Hai d6i ctng lim chung mQt c6ng vi6c sau 15 ngdy xong c6 phuong trinh L 1tt = (l) -+ r 1! 15 n )\ t lim ri6ng vi d6i thu hai ld m tlep cong vrec d6 ngiy thi ca hai dQi hodn thdnh duoc 257,, c6ng vi6c, c6 phuong trinh DQi thu 0,2 !*!=11:i rtl Tu (I Gidi 111 :r ll 15 351 :x?)1 ) va (2) ta cti h6 phuong trinh phuong trinh tim duoc hC !=40 D o i chi6u clidu ki6n vd k€t luAn: d6i thir nhdt I im ri6ng thi sau 24 ngdy xong vi c cl i thu hai lim ri6 thi sau 10 n a xon c oll VICC NI6t b n nu'6c inox c6 d4ng m6t hinh trg v6i chi u cao 1.75 rrr vh diQn tich ilrly 2) li tkii 0.32 nr' I niv tlung tl6y bdn nu'6c du'gc bao nhi6u m6t kh6i n )i n ); n )5 0,5 nu'oc ? (Bri qua bO diy ciia b6n nu'6c) 56 m6t kh6i nu6c bdn dirng ddy bAng th6 tich Bdn nu6c drmg duoc s5 m6t kh6i nuoc ld Gi6i phurrng trinh (z' l) + z)( 'l'H1: r" = TH2: r' - 9e r'' - 7r' - - 0,25 bdn 75 x 32 = 56 (m') 0.2 ); n )i n )\ n 2(v6 nghiQm) :" = hoac r=-3 J - 015 l I 't.rong m{t phing toa d0 (P):u s t,0 0 ) T4p nghiQm phuongtrinh S = vlr parabol 18 crha Or;u cho tlu 2ab - ab -3 vi -3+!=ob*! 222 SI ,7 !.( ab+,t*1 = 4[ 2 ,7 >-ql o,h+=S-' 141 = GTLN cua P =2l.xity rakhi a = 6.r, GTNNcua P=1, xriyrakhi a=b=1 ro\(; t)t[.\l ), I p2 85-4+zr> p> l1 - n toa r 0,2 u=-Ji, t I l 10,0 u 'cl; ,l ... tim duoc hC !=40 D o i chi6u clidu ki6n vd k€t luAn: d6i thir nhdt I im ri6ng thi sau 24 ngdy xong vi c cl i thu hai lim ri6 thi sau 10 n a xon c oll VICC NI6t b n nu'6c inox c6 d4ng m6t hinh... diOm cria do4n thing B(' Du'dng thlng -4 O cdt t4i di6m / dut'ng thing Il-F cit du]ng thnng 11/ tai di6m P Chring minh tam gi{c ;l l'.E- ddng d4ng vcri tam giic AIB vir du'trng thing A1l song... minh ilutrng 0,25 0,25 + b6n didm B.('.8.F ctng thu6c duong tron duong kinh BC thing O.4 vu6ng g6c r'6i itu'tmg ,1i thing EF 1,0 l Ta co B(.:EI: ld tir giric n6i ti6p 2) K6 dudng kinh AQ = +