#### Answer

$x=\dfrac{1-2a^{2}}{1-4a}$

#### Work Step by Step

$\dfrac{x-1}{2a}=2x-a$
Take $2a$ to multiply the right side:
$x-1=2a(2x-a)$
Take $1$ to the right side:
$x=1+2a(2x-a)$
Evaluate the product on the right side:
$x=1+4ax-2a^{2}$
Take $4ax$ to subtract the left side:
$x-4ax=1-2a^{2}$
Take out common factor $x$ from the left side:
$x(1-4a)=1-2a^{2}$
Take $1-4a$ to divide the right side:
$x=\dfrac{1-2a^{2}}{1-4a}$