Solve the following formula for x\displaystyle {x}

y=4x5kx\displaystyle {y}={4}{x}-{5}{k}{x}

x=\displaystyle {x}=  

Enter your answer as an expression.
But be careful...to enter an expression like a+b3+m\displaystyle \frac{{{a}+{b}}}{{{3}+{m}}} you need to type (a+b)/(3+m). You need parentheses for both the numerator and denominator.