Question

Se  $A=2x-1$ e $B=2x+1$, Calcule $A^{2}-B^{2}$ e $(A-B)^2$

Answer 1

$A=2x-1$

$B=2x+1$

$A^{2}-B^{2} = (2x-1)^{2}-(2x+1)^{2} =4 x^{2} -4x+1-(4 x^{2} +4x+1)$$=4 x^{2} -4x+1-4 x^{2} -4x-1=-8x$

$(A-B)^2 = [2x-1-(2x+1)]^2 = [2x-1-2x-1]^2 = [-2]^2 =4$