Question 171607
5.5x -1.5y =3.5
To verify that the answers are correct replace x by 3 & y by 4 and solve.
5.5*3-1.5*4=3.5
16.5-6=3.5
10.5=3.5 does not match. 
Therefore x=3 & y=4 are not valid answers to this equation as stated.