According to the meaning of the question, one class should be given to class two, and there are only so many X books.

Column equation:

48-x=40+x

2x=8

x=4

So class one should give class two four copies, the same amount.

The significance of solving equations:

Solving equations avoids the difficulty of reverse thinking, and can directly list the equations with the quantity to be solved. There are many forms of equations, such as one-dimensional linear equation, two-dimensional linear equation, one-dimensional quadratic equation and so on. , can also be combined into equations to solve multiple unknowns.

In mathematics, an equation is a statement containing one or more variables. Solving an equation involves determining which variables have values that make the equation valid. Variables are also called unknowns, and the value of the unknowns satisfying the equation is called the solution of the equation.