Question

simplify (p+q)^2-(p+q)(p-q)

Answer 1

(p+q)^2-p^2-q^2            (a+b)(a-b) = a^2-b^2

p^2+q^2+2pq-p^2-q^2                (a+b)^2 = a^2+b^2+2ab

=2ab

Answer 2

(p+q)^2-(p+q)(p-q)

Use these identities,And try to solve again,

$(x + y).(x - y) = {x}^{2} - {y}^{2}$
${(x + y)}^{2} = {x}^{2} + {y}^{2} + 2xy$