[tex]f(x)=7x-\dfrac{1}{2}\to y=7x-\dfrac{1}{2}\\\\\text{we change x to y and y to x}\\\\x=7y-\dfrac{1}{2}\\\\\text{solve for y}\\\\7y-\dfrac{1}{2}=x\ \ \ \ |+\dfrac{1}{2}\\\\7y=x+\dfrac{1}{2}\ \ \ \ \ |:7\\\\\boxed{y=\dfrac{1}{7}x+\dfrac{1}{14}}\\\\Answer:\ \boxed{f^{-1}(x)=\dfrac{1}{7}x+\dfrac{1}{14}}[/tex]
