a) Ta có :
\(ac=ab\Rightarrow ac-ab=0\Rightarrow c\left(a-b\right)=0\)
\(\Rightarrow a-b=0\)\(\left(c\ne0\right)\)
\(\Rightarrow a=b\)
b) Ta có:
\(ac>ab\Rightarrow ac-bc>0\)
\(\Rightarrow\left(a-b\right)c>0\)
\(\Rightarrow a-b>0\)
\(\Rightarrow a>b\)
1. Cho a, b, c>0 thỏa mãn a+b +c+ ab+ ac+ bc= 6.
Chứng minh rằng: (a3)/b + (b3)/c+ (c3)/a lon hon hoac bang 3
Cho 2 hinh chu nhat co cung dien tich .HInh 1 co kich thuoc a va b (a lon hon b) hinh 2 co kich thuoc c va d (c lon hon d) .chung minh rang nêu a lon hon c thi chu vi cua hinh1 lon hon chu vi hinh 2
Ax+By=Cz voi cac dieu kien A,B,C,x,y,z deu la cac so nguyen duong, trong do x,y,z lon hon 2con A,B,C có cùng boi số chung nhỏ nhất
ai giải được mình cho 3 like
Cho A=2√x+x\x√x-1 - 1\√x-1 , B=√x+2\x+√x+1 (₫k x lon hon hoac = 0, x khac 9)
a, Tinh B khi x=25
b, Rut gon A
c, Tim x de C=2A:B€Z
Cac ban trinh bay day du giup mk nha.
Bai nao trinh bay dep nhat mk se tick cho nha
cho a>0,b>0 thoa man a+b lon hon hoac bang 2 .tim max cua M =1/a+b^2 +1/b+a^2
lam sao de 2 lon hon 5 ,5 lon hon 0,0 lon hon 2
cho duong tron (O) co BC la day cung co dinh nho hon duong kinh , A la diem di dong tren cung BC lon ( A khong trung B va C). goi AD, BE, CF la duong cao cua tam giac ABC, EF cat BC tai M. Qua D ke duong thang song song EF cat AB tai P va cat AC tai Q:
a) CM: \(\widehat{BPQ}=\widehat{BCQ}\)va tu giac BPCQ noi tiep
b) CM: tam giac DPF can tai D
c) goi N la trung diem BC. CM: MF.ME=MD.MN
d) CM duong tron ngoai tiep tam giac MPQ luon di qua 1 diem co dinh khi A di dong tren cung lon BC
cho (O;R) diem A nam ngoai duong tron sao cho OA lon hon 2R tu A ve 2 tiep tuyen AB va AC . mot duong thang di qua B va // voi AC cat (O) tai D. AD cat (O) tai E goi M la trung diem cua DE
1) cm A,B,C,O,M cung thuoc duong tron
2) OA va BC cat nhau tai H. cm OHED noi tiep
cho OA= Rcăn10. cm BD= 5R/6
moi nguoi oi giúp mk xdkd rút gọn biểu thức khi nao lon hon bang 0 khi nao lon hon 0
trong truong hop nao ccgiup mk vs nhe
