Question

let r be a relation define onset of whole numbers such that R ={(x,y):2x+5y=30,x,y€ W}.write the relation in roster form hence find its domain and range of R

Answer 1

W is the set of whole numbers . ie, natural numbers including zero.
realtion given is 2x+3y=30
start putting numbers for x and find y.
if x=0 then y=10
if x=1 then y=9.33 which is not among W.(Hence (1,9.33) is not in the roster form.)
continue this untill reach x=15 then y=0.No other value is possible for x
so roster form R={(0,10),(3,8),(6,6),(9,4),(12,2),(15,0)}
Domain is the set of x and range is set of all y.
Domain={0,3,6,9,12,15}
Range={10,8,6,4,2,0}