Question 171501
(3,4) is certainly A solution to your equation because


{{{5.5(3) -1.5(4)= 3.5(3)}}}


{{{16.5-6=10.5}}}


However, it is not the only solution.  In fact, any two numbers that are in proportion 3:4 will satisfy the equation and that means that the solution set has infinite elements.  What I suspect is that there is another constraint on the problem that you haven't mentioned (and perhaps your daughter has failed to mention to you) that will uniquely determine a single ordered pair as the solution set.


If this equation is the result of interpretation of a word problem, share the word problem as stated and perhaps there is a clue to that other constraint that you are missing.


Hope this helps.


John