Question 144662
f(x)=x^2-4
f(x)=(x-2)(x+2)
x-2=0
x=2 or (2,0)
x+2=0
x=-2 or (-2,0)
y=-4 or (0,-4)
{{{ graph( 300, 200, -6, 5, -10, 10, x^2 -4) }}} (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, x^2 -4).