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Need help on this question, please.

The sides of a rectangle have lengths x+1 and widths x-5, Which equation below describes the perimeter, P, of the rectangle in terms of x?

[A] P= x2+6x-5
[B] P= 2x-4
[C] P= x-4
[D] P=4x-8

I'm thinking it's letter A because when multiplying two polynomials, you combine the terms.

You know there's one side (x+1) which must be the length of the opposite side to it, and vice versa with the side with length (x-5) so theres 2 of (x-5) sides, and 2 of (x+1) sides. This combined adds up to the perimeter.

2(x+1) + 2(x-5)
= 2x + 2 + 2x - 10
= 4x - 8

Voila