Answer:
When we solve a system of equations, we are looking for the points at which both graphs intercept. Solving a system of equations sometimes can be hard, and you should use other methods -Like numeric methods- to solve it. That's why sometimes is easier to look at the graph of the equation.
To solve a equation, system of equations or a system of inequalities, we should graph each of the equations separatedly, and the result will be the point at which the functions intercept or a single function intercepts the x-axis.
If the function does not intercept another function or the x-axis, then it has no real roots. The number of solutions an equation can have, will depend on the degree of the equation.