(x³-3x²-9x+27)¹/²·(3-x)⁻¹=[x²(x-3)-9(x-3)]¹/²·(3-x)⁻¹==[(x²-9)(x-3)]¹/²·(3-x)⁻¹=[(x-3)(x+3)(x-3)]¹/²·(3-x)⁻¹==[(x-3)²(x+3)]¹/²·[-(x-3)]⁻¹=(x-3)(x+3)¹/²·(x-3)⁻¹=-(x-3)¹⁻¹·(x+3)¹/²==-(x+3)¹/²;(x-18√(x-81))¹/² -(x+18√(x-81))¹/²=-6;⇒[(x-18√(x-81))¹/²-(x+18√(x-81))¹/²]²=(-6)²;⇒(x-18√(x-81)-2·(x-18√(x-81))¹/²·(x+18√(x-81))¹/²+(x+18√(x-81)=36;⇒(2x-2·[x²-18²·(x-81)]¹/²=36;⇒[x²-18²(x-81)]¹/²=-(36-2x)/2;⇒(x²-324x+26244)=(-18+x)²;⇒x²-324x+26244=(324-36x+x²);⇒x²-324x-x²+36x=324-26244;⇒-288x=-25920;⇒x=25920/288=90