So replace x as 12 now you rewrite the problem as 12+4b=72
Now you would have to move the constant towards the right side within it’s sign
4b=72-12
Now you subtract 72 by 12 which would give you 60
4b=60
Then you divide 4 by both sides
Therefore the answer is going to be b=15
b=15
To check do 12+4(15)=72
And that’s accurate