$1)_{}$ $x^2-7xy+10y^2_{}$
$⇔x^2-5xy-2xy+10y^2_{}$
$⇔x.(x-5y)-2y.(x-5y)_{}$
$⇔(x-2y)(x-5y)_{}$
$2)_{}$ $x^3-5x^2-14x_{}$
$⇔x^3+2x^2-7x^2-14x_{}$
$⇔x^2.(x+2)-7x.(x+2)_{}$
$⇔(x^2-7x).(x+2)_{}$
$⇔x.(x-7)(x+2)_{}$
$3)_{}$ $x^2yz+5xyz-14yz_{}$
$⇔yz.(x^2+5x-14)_{}$
$⇔yz.(x^2+7x-2x-14)_{}$
$⇔yz.[ x.(x+7)-2.(x+7)]_{}$
$⇔yz.(x+7).(x-2)_{}$
$5)_{}$ $x^3+4x^2-29x+24_{}$
$⇔x^3-x^2+5x^2-5x-24x+24_{}$
$⇔x^2.(x-1)+5x.(x-1)-24.(x-1)_{}$
$⇔(x-1).(x^2+5x-24)_{}$
$⇔(x-1)(x^2+8x-3x-24)_{}$
$⇔(x-1). [ x.(x+8)-3.(x+8)]_{}$
$⇔(x-1)(x+8)(x-3)_{}$
$4)_{}$ $a^4+4a^2-5_{}$
$⇔a^4+5a^2-a^2-5_{}$
$⇔a^2.(a^2+5)-(a^2+5)_{}$
$⇔(a^2+5)(a^2-1)_{}$
$⇔(a^2+5)(a-1)(a+1)_{}$
