Math: x^2 + bx + c please help.

[From: ] [author: ] [Date: 11-05-05] [Hit: ]

-Will explain the first one then answer the rest :)1. x² + 10x + 24You want to separate it into two brackets, so you have two binomials.You need two numbers that times to get 24, but also add to get 10x.As there is only one x² then you know that BOTH binomials contain x ( x times x is x²)Therefore you can start with: (x +/- a)(x +/- b)Now you need the two numbers that times to get 24 and add to get 10x.......

rewriting f^2 +7f-4f-28=f(f+7)-4(f+7)=(f+7)(f-4)

19. p^2 -2p -8 factor pairs of 8= (1,8) (2,4)
I choose (2,4) because 2-4=-2 and 2*-4=-8
rewriting p^2 -4p+2p-8 = p(p-4)+2(p-4)=(p+2)(p-4)
I used this method because when you go to next stage it will be most useful. I have selected few questions to answer as it will be unfair for me to do all questions and leave nothing for you to practise.

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Will explain the first one then answer the rest :)

1. x² + 10x + 24
You want to separate it into two brackets, so you have two binomials.
You need two numbers that times to get 24, but also add to get 10x.
As there is only one x² then you know that BOTH binomials contain x ( x times x is x²)
Therefore you can start with:
(x +/- a)(x +/- b)
Now you need the two numbers that times to get 24 and add to get 10x....in this case it would be 6 and 4, so you're left with:
(x + 6)(x + 4)

Now i'll just answer the others:

2.(y + 2)(y + 10)
3.(a + 6)(a + 9)
4.(h + 3)(h + 15)
5.(x + 4)(x + 12)
6.(c + 5)(C + 10)
7.(x - 12)(x - 4)
8.(d - 11)(d - 8)
9.(x - 2)(x - 18)
10.(m - 1)(m - 42)
11.(x - 2)(x - 14)
12.(n - 5)(n - 7)
13.(f + 7)(f - 4)
14.(b + 14)(b - 3)
15.(x + 20)(x - 8)
16.(g + 8)(g - 6)
17.(k + 18)(k - 2)
18.(x + 9)(x - 7)
19.(p + 2)(p - 4)
20.(x + 8)(x - 7)
21.(q + 3)(q - 6)
22.(x + 4)(x - 8)
23. Can't do it, typed wrong possibly?
24.(w + 5)(x - 25)

Hope it helped!

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