x 1 2 3 4 5
y 3 6 9 12 15

Given the table, write an expression for the function, and describe what it does.
A) y = 2x. y is double x.
B) y = 3x. y is triple x.
C) y = 2x+1. y is twice x plus 1.
D) y = 2x-1. y is twice x minus 1.