Pls help!
Factor: z^2 -20z + 100

(z-10)²

Step-by-step explanation:

There are multiple ways of factorisation for ax²+bx+c. The easiest here is by finding 2 numbers (let's say a and b) that multiply to get c (in this case, 100), and add to get b (in this case, -20). This gives a result of (x+a)(x+b). This method only works when a=1 (which is true in this case).

For z²-20z+100, the z is the same as the x above is.

Since we are looking for 2 numbers to multiply to a positive, the 2 values must both be positive or both be negative. Adding 2 positives gives a positive result, which doesn't work here, so we must use 2 negatives.

From here, it's just a case of trial and error through the negative factor pairs of 100 (-1 and -100, -2 and -50, -4 and -25, -5 and -20, -10 and -10).

The only result here that adds to give -20 is -10 and -10.

This can be placed in the factorised form of (z-10)(z-10), as described above.

Since both brackets are the same, it can be simplified to (z-10)².

**You may want to revise factorising monic quadratics, and then move on to non-monic ones. I'm always happy to help!

The answer is that both plans are equal.

Step-by-step explanation:

you start by putting the plans into an equation then you set them equal to each other. you need to assign a variable for the number of months. we'll call it M. It would look like this:

plan A - 25 + 8M

plan B - 5 + 12M

25 + 8M = 5 + 12M

Then you solve which looks like this:

25 + 8M = 5 + 12M

     -8M            -8M

25 = 5 + 4M

-5    -5

20 = 4M

/4       /4

5 = M

Now we aren't done after finding out what M equals. We still need to know what each plan will cost. So, we substitute what M equals into the equation. if they both end up equaling the same thing then its equal. if you get two different numbers they aren't. it would look like this:

25 + 8(5) = 5 + 12(5)

25 + 40 =  5 + 60

65 = 65

They are equal. Both plans will cost 65 dollars.