Question

se considera expresia E(x)=(x-1)²+(x+4)(x-3)-2(x²-4) unde x este nr natural real demonstreaza ca E(x)=-x-3 pentru orice numar real x​

Answer 1

$\displaystyle\\\rm\\E(x)=(x-1)^2+(x+4)(x-3)-2(x^2-4) \\ \\E(x) = x^2-2x+1+x^2-3x+4x-12-2x^2+8 \\ \\E(x) = x^2 \cdot (1 + 1 - 2) + x \cdot (-2-3+4) + 1-12+8 \\ \\E(x) = -x -3$