I am trying to help my son with Algebra - can you anwer this?

Question

We have 40 of these problems - but I think if I see one I can get the jist and show him.

Factoring Trinomials - x2 _ 8x - 9

the x2 is x squared.

thanks

it is x2 + 8x -9

Answer 1

You have to find the two polynomials that when multiplied by each other will equal the trinomial.

x2 + 8x - 9

(x + 9) (x - 1)

x*x + -1x + 9x -9

x2 + 8x - 9

Answer 2

x^2 + 8x - 9 = (x - 1)(x + 9)

To determine the correct numbers, consider the number without an x. 9 can be broken down to 1*9 and 3*3. Now look at the number with x to the first power. No amount of adding or subtracting two 3's is going to help, but 9 - 1 works. If x^2 has a coefficient things can be a little more complicated. Please check the reference link if you need more help.

Answer 3

in factoring trinomials, you want to break it down to two (x +- #) equations. the last numbers should multiply to get the last value in the problem, and then add to make the second term.

example

x2 + 8 -9 breaks into
(x + 9) (x - 1)
9 times -1 is -9
9 plus -1 is eight.

thast the Foil property.

Answer 4

you factor it, and when doing that you put it in the (x+9)(x-1) and if you F.O.I.L it you will get the orginal problem the way you figure yout the two numbers to use is the numbers have to add up to the middle term and multiply by the ending term ...for example... 9-1=8 and 9*-1= -9 ....help any?

Answer 5

Use the method called FOIL (first, outside, inside last)

The answer is (x+9)(x-1)

This is so because the first thing in each binomial multiplied is x^2
The outside 2 things multiplied is -1x
The inside 2 things is +9x
The last 2 things is -9

Combine outside and inside to get +8x which is what you needed

Answer 6

x^2-8x-9
split -8 in such way that the sum is -8 and the product is -9
it will be -9 and +1
now rewrite the equation splitting the middle term
x^2-9x+x-9
=x(x-9)+1(x-9)
=(x-9)(x+1)

Answer 7

x^2 + 8x - 9
=(x + a)( x + b)
= x^2 + (a+b)x + ab
so a+b = 8 equation 1
and ab=-9 equation 2
you should be able to see that a=9 and b=-1 fits.
so =(x+9)(x-1).

Answer 8

in case you replace the vales for x, y and z, your equation shoul be -3-(-7) +5. once you subtract an damaging quantity it turns into valuable so your new equation is -3 +7 +5 which equals 9. (in case you have been including a damaging quantity (-3 + -7) then the respond wold be -10.)

Answer 9

Easiest way...think of the factors of negative nine that would equal positive eight. (x+9)(x-1)