a,$x-39=\frac{4}{5}x-\frac{2}{5}+\frac{3x}{5}$
$x-\frac{4}{5}x-\frac{3x}{5}=39-\frac{2}{5}$
....
b, $<=>x^2-4x+4=2x^2-7x+6$
$<=> x^2-3x+2=0$
$<=> (x-1)(x-2)=0$
....
c, wth :| ?
d, đk:....
$<=> \frac{3x+9}{2x^2+5x-3}-\frac{10x-5}{2x^2+5x-3}-\frac{9}{2x^2+5x-3}=0$
.....