Example: x − 2 = 4When we put 6 in place of x we get:6 − 2 = 4which is trueSo x = 6 is a solution.How about other values for x ? For x=5 we get "5−2=4" which is not true, so x=5 is not a solution.For x=9 we get "9−2=4" which is not true, so x=9 is not a solution.etcIn this case x = 6 is the only solution