Question

how to graph y = x - 3

Answer 1

You want to know how to plot it by hand or on a calculator or other software?

Answer 2

i want to know how to plot it by hand

Answer 3

So if plotting by hand:
y = x - 3
you can just work your way around, so you can say okay if x=0 what does y equal, which would be y=-3 then plot that point, next go to x=1, now y=-2 plot that point, you can repeat this as many times as you feel necessary or until you see the trend, then connect the dots :)