Question

a linear equation has solutions (-3,3),(0,0),(-3,-3),then it is of the form y-x=0.comment and justify

Answer 1

Yep, 
(-3,3) = 0
(0,0) = 0
(-3,-3) = 0

Answer 2

The linear equation is of the form y-x=0
because 3-3=0
and -3-(-3)=0