please can someone tell me what HCF and LCF is and their defferences because i always get find them confusing​

Acable company wants to provide cell phone service for residents on an island. the function for the cost of laying the cable from the island to the mainland is c(x)= 6.500 square root x2+4, where x represents the length of the cable in feet. what are the domain and range of the function? a) domain: all real numbers range: all real numbers greater than or equal to 17,000 b) domain: all real numbers greater than or equal to 0 range: all real numbers greater than or equal to 17,000 c) domain: all real numbers greater than or equal to 0 range: all real numbers greater than or equal to 13,000 d) domain: all real numbers greater than or equal to 13,000 range: all real numbers greater than or equal to 0

Susie wants to take her friend out for lunch. she wants to spend $9.75 each person. how much will she spend in all.

For a function f(x), a) if f(7) = 22 then f^-1(22) = b) f^-1(f(c)) =