-x²+√2 x+4 =-(x^2-√2x)+4 =-(x^2-√2x+1/2)+4+1/2=9/2-(x-√2/2)^2=(3√2/2-x+√2/2)(3√2/2+x-√2/2)=(2√2-x)(√2+x)
不是方程啊