Question

(p + q + r) ( p – q + r) + pq - qr.

Simpliely​

Answer 1

Answer:

The answer is $p^2-q^2+r^2+pq-qr+2pr$

Step-by-step explanation:

 $(p+q+r)(p-q+r)+pq-qr$

$=[(p+r)+q][(p+r)-q]+pq-qr$, write in the form of $(a+b)(a-b)$

$=[(p+r)^2-q^2]+pq-qr$, using $(a+b)(a-b)=a^2-b^2$

$=p^2+r^2+2pr-q^2+pq-qr\\=p^2-q^2+r^2+pq-qr+2pr$