# Maths question help ?

Solve by factorising x squared + 9x+20=0

### 15 Answers

- Engr. RonaldLv 72 months ago
x^2 + 9x + 20 = 0

(x + 4)(x + 5) = 0

x + 4 =0 , x + 5 = 0

x = - 4, x = - 5

x = - 4, - 5 answer//

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- KrishnamurthyLv 72 months ago
x^2 + 9x + 20 = 0

x^2 + 5x + 4x + 20 = 0

x(x + 5) + 4(x + 5) = 0

(x + 5)(x + 4) = 0

Solutions:

x = -5

x = -4

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- Anonymous2 months ago
I did it in my mind the answer

Solutions:

x = -5

x = -4

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- sepiaLv 72 months ago
x^2 + 9x + 20 = 0

(x + 5)(x + 4) = 0

Solutions:

x = -5

x = -4

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- 2 months ago
distribute 42 birds in 7 cages each contain an odd number?

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- Ian HLv 72 months ago
Here is an explanation of how to do this example.

If you multiply out two factors such as (x + a)(x + b) you get

x^2 + (a + b)x + a*b,

so now compare that with your example

x^2 + 9x + 20 = 0

You need two numbers that add to make 9 and multiply to make 20.

That is easy, because 4 *5 = 20 and 4 + 5 = 9, so now you can write

x^2 + 9x + 20 = (x + 4)(x + 5) = 0

Either x + 4 = 0. which makes x = -4, or,

x + 5 = 0. which makes x = -5

You were expected to know this method already, so, I suggest that

you remember it now as it will be needed many times.

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- RealProLv 72 months ago
You must be the laziest child in existence. Google it.

- Peter2 months agoReport
There is no need to call her/him that. I forget things too after a while

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- Anonymous2 months ago
YOU ARE LAZY AND DISHONEST BY ASKING STRANGERS TO DO YOUR HOMEWORK. IF YOU TOLD YOUR TEACHER YOU DID IT YOU WOULD FAIL.

And you SHOULD FAIL as you are cheating.

- ...Show all comments
Please dont talk to this lady like this

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- Iggy RockoLv 72 months ago
x^2 + 9x + 20 = 0

(x + 5)(x + 4) = 0

x = -5 or x = -4

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