what is the best first step in solving the formula for b

Answer:
see explanation
Step-by-step explanation:
given
c = [tex]\sqrt{a^2+b^2}[/tex]
The first step is to square both sides, giving ← best first step
c² = ([tex]\sqrt{a^2+b^2}[/tex])², that is
c² = a² + b² ( subtract a² from both sides )
c² - a² = b² ← take the square root of both sides
b = [tex]\sqrt{c^2-a^2}[/tex]