x^2+5x+k^2=2kx+5k-6 x^2-2kx+5x+k^2-5k+6 =0(x-k)^2+5(x-k)+6=0(x-k+3)(x-k+2)=0x=k-3或x=k-2x^-(2√2+3√3)x+6√6=0 (x-2√2)(x-3√3)=0x=2√2或x=3√3