This app solves quadratic equations (ax²+bx+c=0), so you get the points where y=0. When you write in the first box a 0, you can also get the zero points of a linear equation.

When the checkbox in menu-> Settings is checked, you also get complex numbers as results.

When you want an older version of this app, visit my website (link down). At the moment the website is only in german.

Screenshots: