Question 28540
we got f(x)=-3=y say..as usual.we give different values for x and find corresponding value of y
let us give x=0..then y=-3 since y does not depend on x as per the function given.so , whatever my be the value of x ,y is always -3.so the table is 

x=.....0.......1........2.........3.......4.........etc..........
y=.....-3......-3.......-3........-3.......-3........etc..
now you can plot and see.it will be a line parallel to x axis passing through y=-3,whatever may be the value of x.

{{{ graph( 500, 500, -10, 10, -10, 10, 3) }}}