How do you factor p^2-14p+49p214p+49 using the perfect squares formula?

2 Answers
Apr 15, 2017

(p-7)(p-7)(p7)(p7)

Explanation:

49 is 7^272 so we need to make -14p and +49; therefore both signs in the brackets must minus.

(p-7)(p-7)(p7)(p7)

Tip; The perfect square formula can be a bit confusing. Just use your intuition if you know the answer. That is what I do and I do not get penalised for it. Just use the formula if necessary.

Apr 15, 2017

See below.

Explanation:

The perfect squares formula is in the form: (x-a)^2(xa)2. Expanding,

(x-a)^2=x^2-2ax+a^2(xa)2=x22ax+a2

Set this equal to x^2-14x+49x214x+49.

So:

a^2=49a2=49, or a=\pm7a=±7

But,

-2ax=-14x2ax=14x, so a=7a=7.

Thus, p^2-14p+49=(p-7)^2p214p+49=(p7)2.

Or, factor by splitting.

p^2-7p-7p+49p27p7p+49

p(p-7)-7(p-7)p(p7)7(p7)

(p-7)(p-7)(p7)(p7)

=(p-7)^2=(p7)2