Question

(a+b) • (a-b) qual valor?

Answer 1

= (a + b).(a - b)

= a.a - a.b + a.b + b.(-b)

= a² - ab + ab - b²

= a² - b²

R.: a² - b²

Answer 2

(a+b).(a-b)= a^2-b^2  conta  
+a.+a ---> +a.-b--> +b.+a--> -b.-b = a^2 -ab +ab - b^2= corta -ab e+ab =a^2-b^2