How do I find the solutions and factors of a function when given only the graph?
Use the graph to find the zeroes of the function. So, you find the points at which the function crosses the x-axis.
If f(x)=0 for x = x1, x = x2, x = x3, then:
f(x) = (x-x1)(x-x2)(x-x3) g(x)
where g(x) has no zeroes.