a/5=b/7=c/3=> a^2/25=b^2/49=c^2/9
=> a^2+b^2-c^2/25+49-9
=> 585/65=9
=> a^2/25=9
=> a^2=225
=> a=±15
b^2/49=9
=> b^2=441
=> b=±21
c^2/9=9
=> c^2=81
=> c=±9
a) cho 2 stn a va b voi a<b thoa man 3(a+b) =5(a-b)
tim thuong cua 2 so
b) Tim cac so Nguyen Duong a, b, c biet rang : a3-b3-c3 =3abc va a2=2(b+c)
Cho a,b,c la ba so thuc duong thoa man (a^2).(b+c)=(b^2).(a+c)=20172018.tinh (c^2).(a+b)
cau 1 ,cho m,n thuoc n va p la so nguyen to thoa man p/m-1=m+n/p
CMRp^2=n+2
cau 2,cho a,b,c thoa man a+b+c=0 CMRab+bc+ca be hon hoac bang 0
cau 3,bay gio la 4 gio 10 phut hoi sau it nhat bao lau thi hai kim dong ho nam doi dien nhau tren mot duong thang
cau 4,so 2^100 viet trong he thap phan tao thanh 1 so hoi so do co bao nhieu chu so
cau 5,cho a,b,c la so do 3 canh cua mot tam giac vuong voi c la so do canh huyen CMRa^2n+b^2n be hon hoac bang c^2n (n la so tu nhien lon hon 0 )
Cho 3 so a,b,c khac 0 va doi mot khac nhau thoa man a^2.(b+c)=b^2.(a+c)=2015 Tinh c^2.(a+b)
cho x,y,z la cac so nguyen duong va x+y+z la so le, cac so thuc a,b,c thoa man (a-b)/x=(b-c)/y=(a-c)/z. chung minh rang a=b=c
cho 2 so a va b duong thoa man a+b=a^2+b^2=a^3+b^3.tinha^2012*b^2013
tim bo ba so (a;b;c) thoa man: a+b-1/c = b+c-2/a = c+a+3/b = 2/a+b+c
cho 3 so a, b, c va thoa man
ac=b^2; ab=c^2
hay tinh M = a^2011/b^1005.c^1006
cho ba so a,b,c thoa man 0be honhoac bang a be hon hoac bang b+1 be hon hoac bang c+2 va a+b+c=1 tim gia tri nho nhat cua c
