A solution is
the line of reasoning which gives the answer to a mathematical problem.
It is also used for the finals answer if there is one. Consider,
for example, the line of reasoning to find the value of x to satisfy
the equation

3(x - 4) = x - 6.

Multiplying out
the bracket gives 3x - 12 = x - 6

Adding 12 and taking away x gives 3x - x = 12 - 6

Simplifying gives 2x = 6

Dividing by 2 gives x = 3

Then x = 3 is the solution of the equation.