Come consideri # x ^ 2-9 #?
Come consideri # x ^ 2-9 #? Risposta: #(x-3)(x+3)# Spiegazione: #x^2-9″ is a “color(blue)”difference of squares”# #”and in general factorises as”# #•color(white)(x)a^2-b^2=(a-b)(a+b)# #”here “a=x” and “b=3# #rArrx^2-9=(x-3)(x+3)#