Trtcs Dtal t+;
PHONG GIAO DUC VA DAO TAO OTEN CHAU
pt rnr voxc r, cHeN Hec slrlH cr6 HrryEN Lop 9
NAnl Hoc zorT-20r8
ivrONI: roAN 1 inat gian ldm bdi I50 philt)
q1(3,0 arcm1
c6 hai chfi s6 bitit ring sO OO bd"g binh phuong
@ Tim mQt s6 chinh phuong
. cria t6ng c6c chfl s6 cria n6. r
b) Chtmg minh ring: Voi n ld sd tU nhi6n thi n5 - n chia h6t cho t0
Cffu 2 (6,0 di€m). Giai c6c phuong trinh sau:
a) ^l,t+3 +JA =2;
. b) (.,6.5 -6)(r*J7*z'*ro)=r;
c) x2 +3x +l = (x +Z>Jf +t .
CAu 3(8, 0 di€n)
Cho tarn gi6c ABC vu6ng cdn tpi A (BC: a). Gqi M le trunq di6m cria BC;
G ld mQt tliOm tr6n cpnh ABlsao cho GB :2GA. C6c dudng thing GM vd CA
cit rfiau tai D. Dudrng thEng qua M vu6ng g6c v6i CG tai E cdt AC t4i K vA
'rZ
^dudng thang AB tai I .
La) TinhCG theo a;
tb) Chirng minh: . Sj:J:3e.t6m tam gi6c BCD;
' BCID h hinh vudng;
Ogc: DE.
7 GK cit DE tpi P. Chimg minh tam gi6c PGE cdn.
Ciu 4(3,0 diem)
a) Tim gi6 tri lcrn nhdt ctra bi6u thirc:
2-4x
p : 2or7 -'::!. H -L
x'+2 n
6,
Cho x, y, z ld 3 sti ducrng thoi mf,n *' + y' + z' < 6
Tim gi6 tri nh6 nh6t cria biOu thrlc: Q = L * L* I
H€t
xy yz zx