1)hay thay a=3b-1 vao dang thuc 5b+4a=30 va tim a,b?.Giai bang ki nang thay the.

2)tim hai so a va b thoa man a+5b=35 va a-2b=14?.GIAI BANG CACH bien doi  dai so.

d)tim hai so a va b thoa man 2a-10=5b va 4a+3b=150?Giaibang cach bien doi dai so.

Cho cac so a;b;c;d thoa man -2<a;b;c;d<5 va a+2b+3c+5d=10 . CM a^2+2b^2+3c^2+5d^2<140

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

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)

tim cac bo 2 so tu nhien a,b khac 0 thoa man: 1/a+1/b=5/6

tim cac so nguyen duong a,b,c thoa man a+b+c=91 va b^2=a*c

Tim tat ca bo ba so nguyen (a,b,c) thoa man

a^3(b-c)+b^3(c-a) + c^3(a-b)=1964^2013

cho hai so a va b thoa man a+b=19 va 3a/2=2b/5 

vay 2a-3b=?

cho a,b,c la cac so thuc thoa man a+2b-3b=0 va bc +2ac-3ab=o.chung minh a=b=c