Question 474903
a)  Remove grouping symbols:
    m(m-4)

multiply each term in the Parenthesis by the m outside it

m*m-m*4
m^2-4m
b)  Remove grouping symbols and collect like terms:
    2(3m+1)-3(5-2m)
Similarly 
2*3m+2*1 -3*5+(-3*-2m)
6m+2-15+6m
group the similar terms
6m+6m+2-15
12m -13