Answer:
2(b+4)
2(a-4)
2(a+4)
Remember that simplify is writing a expression in the most compact way, without changing the value of the expression.
You can simplify this three expression taking out common factor 2.
Then you can find that:
2b+8 is equal to 2(b+4) because 2*b+2*4=2b+8
in the same way:
2a-8 is equal to 2(a-4) because 2*a-2*4=2a-8
and
2(a+4) is equal to 2(a+4) because 2*a+2*4=2a+8