Question 1161810
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The expressions are linear; there will not be two different answers.<br>
The problem with the solution by tutor @josgaritihmetic is that it uses two different interpretations of "the difference of a and b".<br>
In everyday language, a difference is nearly always assumed to be a positive number.  For example, if a man is 40 and his wife is 35, then the difference of the man's age and the wife's age is 5 years, and the difference of the wife's age and the man's age is 5 years.<br>
But in mathematics, you can't have two different interpretations of "difference".<br>
Mathematically, the difference of the man's age and his wife's age is 5; the difference of the wife's age and the man's age is -5.<br>
In other words, mathematically, the difference of A and B is ALWAYS A-B; it is NEVER B-A.<br>