Respuesta :
we can do anything to an equation as long as we do it to both sides
remember the associative property of addition
a+(b+c)=(a+b)+c
so
12+(7+m)=(12+7)+m=19+m
19+m=30
minus 19 both sides
19-19+m=30-19
0+m=11
m=11
remember the associative property of addition
a+(b+c)=(a+b)+c
so
12+(7+m)=(12+7)+m=19+m
19+m=30
minus 19 both sides
19-19+m=30-19
0+m=11
m=11
