Question

Efectuati următoarele calcule :
a)(2x+3)^2 -(2x-3)(2x+3)+2(x-1)^2

Answer 1

$\displaystyle (2x+3)^2-(2x-3)(2x+3)+2(x-1)^2= \\ =(2x)^2+2 \cdot 2x \cdot 3+3^2-(4x^2-9)+2(x^2-2 \cdot x \cdot 1+1^2)= \\ =4x^ 2+12x+9-4x^2+9+2(x^2-2x+1)= \\ =4x^2+12x+9-4x^2+9+2x^2-4x+2= \\ =2x^2+8x+20$