Question

(5m+n)(n-5m)-25m(m-6)

Answer 1

(5m+n)(n-5m)-25m(m-6)=5mn-25m^2+n^2-5mn-25m^2+150m=-50m^2+n^2+150m

Answer 2

простите, 150m

Answer 3

(5mn-25m^2+n^2-5mn)-(25m^2-150m)
5mn-25m^2+n^2-5mn-25m^2+150m
-50m^2+n^2=150m 
Вроде так.

Answer 4

+150m*