The curve is a quadratic equation because it has a x^2 - as it is positive it will be a u shaped parabola. The equation can be factorised by thinking of two numbers which add to make 4 (the b value) and multiply to make 4 (the c value). This gives (x+2)^2.You make it equal to 0, giving a value of x=-2. This is a repeated root meaning that the trough of the curve will touch the x-axis at -2. The y-intercept can be found by substituting a value of x=0 into the equation. This gives the co-ordinate (0,4). The sketch will be drawn on the whiteboard.