$a)_{}$ $4x.(x-5)-(x-1)(4x-3)=5_{}$
$⇔_{}$ $4x^2-20x-(4x^2-3x-4x+3)=5_{}$
$⇔4x^2-20x-4x^2+3x+4x-3=5_{}$
$⇔-13x-3=5_{}$
$⇔-13x=8_{}$
$⇔x=_{}$ $-\frac{8}{13}$
$Vậy_{}$ $x=_{}$ $-\frac{8}{13}$
$b)_{}$ $(x-5)(x-4)-(x+1)(x-2)=7_{}$
$⇔x^2-4x-5x+20-(x^2-2x+x-2)=7_{}$
$⇔x^2-9x+20-x^2+x+2=7_{}$
$⇔-8x+22=7_{}$
$⇔-8x=-15_{}$
$⇔x=_{}$ $\frac{15}{8}$
$Vậy_{}$ $x=_{}$ $\frac{15}{8}$
