khanh.huynhquoc.googlepages.comPHN I SCC HNG NG THC NG NH.
HM S BC NHTy = ax + b:1.C h s gc l a; tung gc l b.2.ng bin
trongton min xcnhnu a > 0; Nghch bin trong ton min xcnhnu a <
0.3.C th l ngthng + Ct trc tung ti im c tung bng b (ta l (0;b));
+Ct trc honh ti im c ta l (-b/a;0).4.Gc to bi th v trc honh l gc
@:+ nu a > 0th@nhn v a = tang@+ nu a < 0th@t v a = tang@ (@
v@ l hai gc k b nhau)5.Cho hai ng thng (d): y = ax + b (akhc0) v
(d): y = ax + b (akhc0)+(d) v (d) ct nhauaa+(d) v (d) song song
nhaua = avb khcb+(d) v (d) trng nhaua = av b = b
Cc nh ngha; nh l I S 9 quan trng hc k hai.1)Phng trnh bc nht hai
n x,y c dng ax + by = c trong a;b;c l cc s thc; ahocb khc 0.2)Mi
phng trnh bc nht hai n u c v s nghim. Mi nghim ca n l mt cp s (csp
theo th t). Biu din tp nghim ca n ln mt phng ta l mt ngthng.3)Hai h
phng trnh cgi l tng ng nu chng c cng mt tp nghim. 4)Phng trnh bc
hai mt n c dng ax2+ bx + c = 0trong x l n s;a;b;c l cc s thc v a
khc 0.5)Cng thc nghim ca phng trnh bc hai: (Xem sch)6)H thc Vit: Nu
phng trnhax2+ bx + c = 0 c hai nghim th tng hai nghim l -b/a v tch
ca chng l c/a.7)Nu tam thcax2+ bx + c c 2 nghim l m v n th tam thc
c phn tch thnh nhn t bng: a(x-m)(x-n).
