Math Help!! See Below!?

Question

Z to the 2nd power- 9z + 20=

Answer 1

Are you supposed to factor it?

Then it's (z-4)*(z-5).

I did the factoring by finding two numbers whose sum is 9 and whose product is 20. Trying various factors of 20 is the easiest way: 10+2=12, 4+5=9.

Answer 2

z = 4 or z = 5

Answer 3

z^2 - 9z +20

step 1 ----->>(z )(z )
* since z is cubed(raised to the 2nd power) split it up and put each one into parenthesis. (like shown above)
step 2 ----->>(z - 4) (z - 5)
* Look a the numbers (-9) and 20 what numbers will add together to equal (-9) and multiply to make 20?
(-4) + (-5) = (-9) ..... and (-4) * (-5) = (+20)

so, z^2 -9z + 20 = (z-4)(z-5)
If you don't get it, you should ask your teacher.

Answer 4

okay this is basically trying to break down the equation into a simpler form the answer can be found by guessing and checking. The simplified form of the equation turns out to be

(z-4)(z-5)
or
(z-4) x (z-5)

if you use FOIL the answer turns out to be z squared minus 9z plus 20

:)

Answer 5

z^2 - 9z + 20

To factor these quadratics,
1) Look at the middle term (in this case, it's -9)
2) Look at the third term, the one without an x (in this case, it's 20).

This is going to factor in this way:

(z + ?)(z + ?)

Where you fill in the question marks.

You have to ask yourself: What two numbers multiply to make +20 and add to make -9? The answer to that is -4 and -5, so that's what goes in the question marks.

(z - 4)(z - 5)

Answer 6

(z-4)(z-5)
z = 4 or 5

Answer 7

z^2-9z+20=0
(z-4) * (z -5) = 0
z-4 = 0
z-5 = 0

therefore z = 4 or 5.

Answer 8

(z-4)*(z-5)