Question

por favor galera e pra amanhã 9k

Answer 1

2-
a)-9+3=-6
b)-3-9=-12
c)-12+42=30
d)35-20=15
e)-70-42=-112
f)-85-12=-97
g)-90-30=-120
h)15+25=40

4-
a)-9-(+4) --- -9-4=-13
b)(+13)+(-6) --- 13-6=7
c)(-20)-(+40) --- -20-40= -60
d) (-5)-(-3)-(+2)-(-9) ---  -5+3-2+9 --- -7+11=4
e)50-(+75) --- 50-75= -25

5-
a) associaçao
b) neutro
c) associação
d)neutro