√x^2 - 9 - 5√x + 3 = 0; √49.( 1 - 2x + x^2) - 35 = 0

a) $\sqrt{x^2 - 9} - 5 \sqrt{x + 3} = 0$
b) $\sqrt{49 . (1 - 2 x + x^2)} - 35 = 0$