An equation is a mathematical statement such that the expression on the left
side of the equals sign (=) has the same value as the expression on the right side.
An example of an equation is 2 + 2 = 4.
One of the terms in an equation may not be know and needs to be determined. Often
this unknown term is represented by a letter such as x. (e.g. 2 + x = 4).
The solution of an equation is finding the value of the unknown x. To find the
value of x we can use the subtractive equation property which says: The two sides of an
equation remain equal if the same number is subtracted from each side.
Example:
5 + x = 12
5 + x - 5 = 12 - 5
0 + x = 7
x = 7
Check the answer by substituting the answer (7) back into the equation.
5 + 7 = 12