[tex]n-the\ number\\\\n+142=64\cdot3n\\\\n+142=192n\qquad\text{subtract n from both sides}\\\\142=191n\qquad\text{divide both sides by 191}\\\\\dfrac{142}{191}=n\to \boxed{n=\dfrac{142}{191}}[/tex]
[tex]n+142=3n+64\qquad\text{subtract 142 from both sides}\\\\n=3n-78\qquad\text{subtract 3n from both sides}\\\\-2n=-78\qquad\text{divide both sides ny (-2)}\\\\\boxed{n=39}[/tex]
