To solve an equation means to find all the values that make the statement true.
This might be done graphically, but, most of the time it must be done algebraically. To solve an equation graphically, draw the graph for each side, member, of the equation and see where the curves cross, are equal. The x values of these points, are the solutions to the equation.
Consider the following examples.

1.  2.  3.  4. 
5.  6.  7.  
9.  19.  11.  12. 
13.  14.  15.  16. 
1718.  17.  18. 