The value of x, for which the points (x,-1), (2,1) and (4,5) lie on a line is
zero
1
3
2
For what value of x will the points (x, – 1), (2, 1) and (4, 5) lie on a line?
If the points (1,-1), (2,1) and (4,x) lie on a staright line, then x is __