Answer:
[tex]\large\boxed{x=\dfrac{1}{2}}[/tex]
Step-by-step explanation:
[tex]10x-40x=-15\\\\-30x=-15\qquad\text{divide both sides by (-30)}\\\\\dfrac{-30x}{-30}=\dfrac{-15}{-30}\\\\x=\dfrac{1}{2}[/tex]