Xx15+Xx13=560x45
Xx15+Xx13=25200
Xx(15+13)=25200
Xx28=25200
X=25200:28
X=900
X * 15 + X * 13 = 560 * 45
X * (15+13) = 25200
X * 28 = 25200
X = 900
Vậy X = 900
\(x\times15+x\times13=560\times45\)
\(x\left(15+13\right)=560\times45\)
\(x\times28=560\times45\)
\(x\times28=25200\)
\(x=25200\div28\)
\(x=900\)