Explicație pas cu pas:
E(x)=3(x-1)²+(x√2+1)(1-x√2)-x(x-6)
E(x)=3(x²-2x+1)+(1+x√2)(1-x√2)-x²+6x
E(x)=3x²-6x+3+1²-(x√2)²-x²+6x
E(x)=3x²-6x+3+1-2x²-x²+6x
E(x)=4,∀x∈R
