What is the value of $(a+b)^2-(a-b)^2$ ?

$2\left(a^2+b^2\right)$ $4\left(a^2+b^2\right)$ 8ab 4ab

4ab

(a+b)2−(a−b)2 = (a2+2ab+b2)−(a2−2ab+b2) = a2+2ab+b2−a2+2ab−b2 = 4ab.