Answer:
[tex]\large\boxed{x=\dfrac{233}{3}=77\dfrac{2}{3}}[/tex]
Step-by-step explanation:
[tex]3x-4y=65\\\\\text{Put}\ y=42\ \text{to the equation and solve for }\ x:\\\\3x-4(42)=65\\\\3x-168=65\qquad\text{add 168 to both sides}\\\\3x-168+168=65+168\\\\3x=233\qquad\text{divide both sides by 3}\\\\\dfrac{3x}{3}=\dfrac{233}{3}\\\\x=\dfrac{233}{3}[/tex]
