Pls help
Question is in the picture

Answer:
c = 9-a+b
Step-by-step explanation:
sqrt( a-b+c) = 3
Square each side
(sqrt( a-b+c))^2 = 3^2
a-b+c = 9
We want to solve for c
Subtract a from each side
a-b+c -a = 9-a
-b+c = 9-a
Add b to each side
-b+c+b = 9-a+b
c = 9-a+b