A variable point P(x,y) traces a graph in a two-dimensional plane. (0,−3) is one position of P. If x increases by 1 unit, y increases by 4 units. The equation of the graph is
Worked solution (try it first)
When x goes up by 1, y goes up by 4, so the gradient is 14=4.
The point (0,−3) is on the y-axis, so the y-intercept is −3 and the line is y=4x−3.