linear euation

Please ask 1 question in 1 query.

 

Answer to your first question is

 

y = (4+4x)/2

 

To check if points A(-1,-1) lie on  the line, just substitute x = -1 and y = -1 and check if LHS = RHS

 

LHS = 2y-4x = 2(-1) - 4(-1)  = 2 which is not equal to RHS and hence, (-1,-1) does not lie on the line. 

 

Similarly for (2,7.5) LHS = 2(7.5) - 4(2) = 15-8 = 7 = RHS and hence, (2, 7.5) lies on the line.