1.(a-√3)(a+√3)-a(a-6) =a^2-3-a^2+6a =6a-3 =6(√5+1/2)-3 =6√5+3-3 =6√5 2. x^2-5x=14 (2x-1)(x-1)-(x+1)^2+1 =2x^2-3x+1-x^2-2x-1+1 =x^2-5x+1 =14+1 =15