Algebraic Expression?

Question

p²+pq-pr+qr
p²+pq+pr+qr

= p(p+q)-r(p+q)
p(p+q)+r(p+q)

= p-r
p+r

Can you all spot any mistakes i made. its fraction actually but since i can't to the line thingy......Why is it wrong?

Answer 1

Be careful with negative signs!!

p²+pq-pr+qr
-----------------
p²+pq+pr+qr


p(p+q)-r(p-q)
-----------------
p(p+q)+r(p+q)

You're mistake is in this step.. If you're factoring out a negative r, you have to change the sign of the q. This is a very common mistake.. It may take a few more examples for you to get familiar with what's going on. Please talk to your teacher about this one to get a better understanding than what I can show you on here.

p(p+q)-r(p-q)
-----------------
p(p+q)+r(p+q)


p(p+q)-r(p-q)
------------------
(p+q)(p+r)

That's it, it doesn't simplify any further.