[tex] \\
1.\;(x-2)^2+(x+2)^2=x^2-4x+4 + x^2+4x+4=2x^2+8\;;\\
2.\;(x-3)^2+(x+3)^2=x^2-6x+9 + x^2+6x+9=2x^2+18\;;\\
3.\;(x-4)^2+(x+4)^2=x^2-8x+16 + x^2+8x+16=2x^2+32\;;\\
4.\;(x-5)^2+(x+5)^2=x^2-10x+25+x^2+10x+25=2x^2+50\;;\\
5.\;(x-6)^2+(x+6)^2=x^2-12x+36+x^2+12x+36=2x^2+72\;;\\[/tex]