Find the indefinite integral of $x\times (5x-1{)}^{19}$ by substitution

My try:

$u=5x-1$, so $\frac{du}{dx}=5$, thus $dx=\frac{du}{5}$

How to cancel out the $x$ in front?

My try:

$u=5x-1$, so $\frac{du}{dx}=5$, thus $dx=\frac{du}{5}$

How to cancel out the $x$ in front?