Which relation is a function of X? Why did I get this wrong? Can I please get an explanation of why I got this wrong and what I need to do next time too get it right

Cumulative examcumulative exam active13time remaining02: 44: 18the graph represents the data cost for monthly internetservice for a cell phone.which function, c(x), represents the monthly cost in dollarsin terms of x, the number of gigabytes used in a month? cell phone internet service(15,5x + 10150,0sx522 < x < 664x115, osx< 25x + 20, 2< x< 650, 65815%,monthly cost (s)20x + 5| 50x,0 < x < 22 < x < 664x( 15x, osx< 2c(x) = 5x + 10, 2< x< 6150x, 65 x5+1234 5 6 7 8 9 10 11 12gigabytes used

An equation where variables are used to represent known values—function notation true or false

The pyramid shown has a square base that is 24 centimeters on each side. the slant height is 16 centimeters. what is the lateral surface area?