Question

Make b the subject of the formula P=2a+b

Answer 1

In order to make b the subject of this equation, we must isolate it on the left side. We can do this by following these steps:

$P = 2a+b$

Subtract b from both sides

$P - b = 2a+b-b$

$P-b=2a$

Subtract P from both sides

$P-b-P=2a-P$

$-b=2a-P$

Now, we have isolated b, but it is negative. We can fix this by multiplying both sides of the equation by -1.

$-(-b)=-(2a-P)$

$b=-2a+P$

Which is your final answer.
$b = -2a+P$.
Hope that helped! =)

Answer 2

If you're trying to isolate b, then you can do the following:

P=2a+b
P-2a=b
b=P-2a

But I'm not sure if that's what it is asking you to do.