f(x)=√x-8. Find f¹(x) and its domain.
O A. f¹(x) = x² +8; xz -8
X
OB. f¹(x) = (x+8)²; x≥0
O c. f¹(x) = (x + 8)²; x≥-8
O D. f¹(x) = x² +8; xz0