When people work with quadratic equations, one of the most common things they do is to "solve" it. This means to find the points on a coordinate grid where the graphed equation crosses the x-axis, or the horizontal axis. These points are called the "zeroes", or "roots", of a function. In other words, to solve the equation means to find the value of "x" so that formula_1, where the coefficients, "a", "b", and "c", are all real numbers. There are different ways to find out the value of x. Plotting the function on a graph is one way. In the picture on the right, the function crosses the x-axis at the points formula_3 and formula_4.