Find and explain the error in the work below.

Multiply: (-4m+2)(2m+5)
-4m(2m)+4m(5)+2(2m)+2(5)
-8m^2+20m+4m+10
-8m^2+24m+10

+4m(5) No it is -4m(5)

here is another way:
-4 m (2 m+5) + 2 (2 m+5)
= -8 m^2 - 20 m + 4 m + 10
= -8 m^2 - 16 m + 10