a/19=b/21
=>2a/38=b/21
áp dụng 2 câu trên Ta có :
2a/38=b/21=2a-b/38-21=34/17=2
=>a/19=2=>a=38
=>b/21=2=>b=42
=>a+b=38+42=80
vậy a+b=80
hai so a;b thoa man a/19=b/21 va 2a-b=34
khi do a+b=
cho hai so a va b thoa man a+b=19 va 3a/2=2b/5
vay 2a-3b=?
cho hai so duong a;b thoa man a/5=b/6 va 2a^2-b^2 =56
khi do a+b=
cho a,b,c la cac so nguyen thoa man cac dieu kien: a+b-c=15; a-b+c=21; -a+b+c=-2015. Tim cac so nguyen do.
so cap so duong a va b thoa man 1/a -1/b=1/a-b
cho 3 so a,b,c thoa man \(\frac{a}{3}\) = \(\frac{b}{8}=\frac{c}{5}\) va 2a+3b-c=50.tinh tong cua 3 so a,b,c bang
tim 3 so a,b,c khac nhau va khac 0 thoa man : a/(b+c) = b/(a+c) = c/(a+b)
cho 2 so a va b duong thoa man a+b=a^2+b^2=a^3+b^3.tinha^2012*b^2013
cho ba so duong a,b,c thoa man: a/5=b/7=c/3 va a^2+b^2-c^2=585 hoi a+b+c=