Help me with these questions, explaining it would be awesome!!

i hope my answer help you:))

Step-by-step explanation:

{1st question}

b=3b-18=12

=3b=12+18

=3b=30 ( divided by 3)

then b=10

{2nd question}

d = -42-7d=49

=-7d=49+42

=-7d=91 ( divided by -7)

then d= -13