How do you solve for an indicated letter in algebra?

seas1456: How do you solve for an indicated letter in algebra?
How do you solve for an indicated letter in algebra? Example b=10-a, solve for a
I am looking for the process not an answer.

Answers and Views:

Answer by Alex T.
You must use INVERSE opperations to isolate a.

First, subtract 10 from both sides:
b = 10-a
b – 10 = 10 -a -10
b-10 = -a

Now, multiply both sides by -1

-b + 10 = a
a = 10-b

Answer by king K
Well b/c you have two unknowns in your equation, you need 2 equations to solve for an indicated letter.

b = 10 – a , to solve for a, add a to both sides
+a +a
—————-
b+a = 10 , now subtract b from both sides
-b -b
—————-
a = 10 – b : to solve for a, you need to know what b is, which another equation can help.