Răspuns :
Sunt fomulele speciale.
[tex](x+3)^{2} =x^{2} +2*x*3+ 3^{2} = x^{2} +6x+9 [/tex]
[tex](x-2)(x+2)= x^{2} -2^{2} = x^{2} -4[/tex]
[tex](2x-5)^{2} = (2x)^{2} -2*2x*5+5^{2} =4 x^{2} -20x+25[/tex]
[tex](x+3)^{2} =x^{2} +2*x*3+ 3^{2} = x^{2} +6x+9 [/tex]
[tex](x-2)(x+2)= x^{2} -2^{2} = x^{2} -4[/tex]
[tex](2x-5)^{2} = (2x)^{2} -2*2x*5+5^{2} =4 x^{2} -20x+25[/tex]