Given l1​ and l2​ are two lines with gradient m1​ and m2​. Write the property of the gradients if l1​ and l2​ are (i) parallel (1) (ii) perpendicular (1) (iii) overlapping (2) (b) Given l1:y=x+1 l2​:y=1−x li :y=2+x l4: 2y=2+2x. Determine which of these lines are parallel, perpendicular or overlapping.