Răspuns:
[tex]E(x)=(x+2)^{2} +(x-3)^{2} +(3x+1)^{2}-(2x-1)^{2} \\\\E(x)=(x^{2} +2*x*2+2^{2} )+(x^{2} -2*x*3+3^{2} )+((3x)^{2}+2*3x*1+1^{2} )-((2x)^{2} -2*2x*1+1^{2} )\\\\E(x)=x^{2} +4x+4+x^{2} -6x+9+9x^{2}+6x+1-4x^{2}+4x-1 \\\\E(x) = 7x^{2} +8x+13[/tex]
Explicație pas cu pas:
[tex](a+b)^{2} = a^{2} +2*a*b+b^{2} \\\\(a-b)^{2} = a^{2} -2*a*b+b^{2}[/tex]
