There are many excellent online resources for learning about and solving equations.
Note that WolframAlpha is excellent for checking solutions to equations.
Note that you can change the equations inside the above widgets.
Alternatively – just type your equation into WolframAlpha.
(Note that step by step solutions are for pro subscribers but you can get answers to as many equations as you want, so WolframAlpha is great for checking work).
Also from Mathisfun we have a Quadratic Equation Solver, simply enter the coefficients (a, b and c) and the solutions and a graph will be returned.
Try this calculator from Math Warehouse which shows the working very clearly using the formula.
For practising solving linear equations Duncan Keith’s excellent linear equation calculator is excellent. The Subtangent resources from Duncan Keith are available from the National Stem Centre (the original site is no longer available).
The slideshow below shows how to use the calculator to solve equations where the unknown is on both sides.