Răspuns: [tex]\bf\red{\underline{ E(x) =8x}}[/tex]
Explicație pas cu pas:
[tex]\bf E(x) = \big(x+2 \big)^2- \big(x-2 \big)^2[/tex]
[tex]\bf E(x) = \big(x^2+2\cdot x\cdot2+2^2 \big)- \big(x^2-2\cdot x\cdot2+2^2 \big)[/tex]
[tex]\bf E(x) = \big(x^2+4x+4 \big)- \big(x^2-4x+4 \big)[/tex]
[tex]\bf E(x) =\not x^2+4x+\not4-\not x^2+4x-\not4[/tex]
[tex]\bf\red{\underline{ E(x) =8x}}[/tex]
In imagine ai formule de calcul prescurtat.
Bafta multa !
