Simplify the polynomial $\left(3 x^{2}+2 x y+5 y^{2}\right)-\left(-7 x^{2}\right.$ $\left.-2 x y+3 y^{2}\right)$

Step 1 ：Given the polynomial \(3 x^{2}+2 x y+5 y^{2}-(-7 x^{2}-2 x y+3 y^{2})\).

Step 2 ：Subtract each corresponding term in the second polynomial from the first one.

Step 3 ：The simplified polynomial is \(\boxed{10x^{2} + 4xy + 2y^{2}}\).