For each of the graphs given in Fig. 4.5 select the equation whose graph it is from the choices given below:

Explanation

(a) In Fig. 4.5 (i), the points on the line are `(–1, –2), (0, 0), (1, 2)`. By inspection, `y= 2x` is the equation corresponding to this graph. You can find that the y-coordinate in each case is double that of the x-coordinate.
(b) In Fig. 4.5 (ii), the points on the line are `(–2, 0), (0, 4), (1, 6)`. You know that the coordinates of the points of the graph (line) satisfy the equation `y= 2x+ 4`. So,`y= 2x+ 4` is the equation corresponding to the graph in Fig. 4.5 (ii).
(c) In Fig. 4.5 (iii), the points on the line are `(–1, –6), (0, –4), (1, –2), (2, 0)`. By inspection, you can see that `y= 2x– 4` is the equation corresponding to the given graph (line)