Answer:
a= 1/2p-b
Step-by-step explanation:
p=2a+b
divide by 2 on both sides
1/2 p = a+b
subtract b from both sides
1/2 p - b = a
flip equation (not needed, just personal preference)
a= 1/2p-b
(Sorry if I didn't understand well enough and got it wrong)
