Explicație pas cu pas:
[tex] E_{(x)} = (x + 3) ^{2} - 2(x - 2)(x + 2) + x(x + 1) - 3x \\ \\ E_{(x)} = {x}^{2} + 2x \times 3 + {3}^{2} - ( {2x}^{2} + 4x - 4x - 8) + {x}^{2} + x - 3x \\ \\ E_{(x)} = {x}^{2} + 6x + 9 - {2x}^{2} - 4x + 4x + 8 + {x}^{2} + x - 3x \\ \\ E_{(x)} = ( {x}^{2} - {2x}^{2} + {x}^{2}) + (6x - 4x + 4x + x - 3x) + (9 + 8) \\ \\ E_{(x)} = 4x + 17 [/tex]