Answer
$x=(21-\sqrt {41})/50$, $x=(21+\sqrt {41})/50$
Work Step by Step
$(5a-2)^2-a=0$
$(5a-2)(5a-2)-a=0$
$5a*5a+5a*-2+5a*-2+(-2)(-2)-a=0$
$25a^2-10a-10a+4-a=0$
$25a^2-21a+4=0$
$a=25$, $b=-21$, $c=4$
$x=(-b±\sqrt {b^2-4ac})/2a$
$x=(-(-21)±\sqrt {(-21)^2-4*25*4})/2*25$
$x=(21±\sqrt {441-400})/50$
$x=(21±\sqrt {41})/50$