Which expression has been rewritten correctly to form a true statement

Step-by-step explanation:

15

It looks like the 4th one is the one you want to investigate. There are two ways you could do it.

I think the second way is easier to do. You will wind up with a quartic (x^4) the first way.

let y = (x^2 - 4)

Therefore z = y^2 - 5y - 6

This factors into

z = (y - 6)(y + 1)

Now put (x^2 - 4) in for y

z = (x^2 - 4 - 6)(x^2 - 4 + 1)

z = (x^2 - 10)(x^2 - 3)

So it looks like I either made the wrong guess, or I made a mistake.

Let's try the first one

Let y =x + 2

y^2+2y -8

=(y +4)(y - 2)

=(x+2 + 4)(x + 2 - 2)

=(x+ 6)(x)

Looks like the first one is the answer.

answer: 12   they all have at least 28 days

step-by-step explanation: haha