Y = x² or y = 3 x +1 equation is given.
Take simple example values of x. Find the corresponding values of y.
Take values like x = -2, -1, -1/2, 0, 1/3, 1/2, 1 , 2, 3, 4, 5
plot (x,y) on the graph, by locating it. Join all the points plotted by straight lines. Connect each point with the next point by a straight line from left to right.