Answer:
[tex]\left(a+b\right)^n=\sum _{i=0}^n\binom{n}{i}a^{\left(n-i\right)}b^i[/tex]
[tex](5x - 2y)^{10} =\sum _{i=0}^{10}\binom{10}{i}\left(5x\right)^{\left(10-i\right)}\left(-2y\right)[/tex]
Coeffecient of x^3y^7=
[tex]\frac{10!}{7!(110-7))!} (5x)^3 (-2y)^7[/tex][tex]=-1920000x^3y^7[/tex]
Ans : -1920000
