(x + 4)(x − 4) Just wanna make shure this is right x^2-16?
Yes, because (x + 4)(x - 4) = x(x - 4) + 4(x - 4) = x^2 - 4x + 4x + 16 = x^2 - 16
It's called difference of squares
ok sweet and then would (x + 4)(x + 4) be x^2+16
Negative
(x + 4)(x − 4) x(x-4)+4(x-4) x2-4x+4x-16 x2-16.
(x + 4)(x + 4) = x(x + 4) + 4(x + 4) = x^2 + 4x + 4x + 16 = x^2 + 8x + 16
It's called a perfect square trinomial.
ok i see
i have to compare and contrast
Any time you have the sum of two numbers times their difference, (a + b)(a - b) you get the difference of two squares: $$a^2-b^2$$
so how to i compare and contrast x^2 - 16 and x^2 + 8x + 16
The first is the difference of two squares: $$x^2 - 16=x^2-4^2$$
ok
One is a difference of squares, the other is a binomial square.
The second is the square of a sum $$(a+b)^2$$
$$(x + 4)^2$$
so the similarity is the 8x
There is no middle term in the difference of two squares.
wait x^2 is a similarity
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