Answer:
By adding 4 to both sides.
2= -4 +b
2= b -4
2+4= b-4 +4
6= b
Another way to look at it is to move all the constants to one side. Here we have the constant 2 on the left hand side, and on the right we have the constant -4 and the variable b.
To isolate b, we move the constant -4 to the left hand side. Moving a number to the other side of the equal sign changes the sign of the number. So, -4 becomes a +4 on the left hand side.
2 +4= b
6= b
