10. (10-m)^2

1. Expand the expression: (10-m)(10-m)

2. Apply the distributive property (FOIL): 10*10 + 10*(-m) + (-m)*10 + (-m)*(-m)

3. Simplify: 100 - 10m - 10m + m^2 = m^2 - 20m + 100