(x+3)(x-2)
x=-3,2
ok x^2 means 2x's, the +x=1x which means that the sum of the 2 numbers is 1 and -6 means the 2 numbers product is -6
or you can use the quatractic formula-if you didn't learn it then you will after that chapter.
2007-12-06 14:38:08
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answer #1
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answered by sumhow 2
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The standard form of an equation is ax^2 + bx + c
Hence in the given equation
a = 1
b = 1
c = -6
Now to solve this equation, you need to find any two number which when added give b, and when multiplied give a * c
i.e. if the 2 numbers are x and y,
x + y = 1
x * y = a * c
Best way to go about this is to find the factors of a * c In this case 6
6 = 6 * 1 or
6 = 3 * 2
If you notice in the standard equation there are no negative signs. However in the given equation c is a negative number and hence a * c will be a negative number. Hence on of the factors of 6 HAS to be a negative number.
As you can see there are only two option that give you 6 here. Now you need to check in which of the cases, the factors when added (don't forget that one of them will be a negative number and hence in reality we'll be subtracting them) give you 6.
Difference between 6 and 1 (the first factors we found) is 5
Similarly the difference between 3 and 2 is 1 <== we have a winner.
So now which of these factors will be the negative number? Look at b. It's a positive number. Hence the bigger of the two factors (3 and 2) cannot be the negative number. So the factors are 3 and -2
You now have to put this into your equation. But how do you know which factor comes first? For that you need to compare a and c. c is the bigger number in this case and hence the smaller factor should be placed closer to c.
Hence this equation x^2 + x - 6 now becomes
x^2 + 3x - 2x - 6
You now take the first 2 components of the equation (i.e. x^2 + 3x). What is common? Just x. We hence take the common factor out and shove the rest in a bracket.
x(x + 3)
We now do the same for the last 2 components (i.e. -2x - 6). -2 is the common factor. Hence
-2 (x + 3)
NOTE that whatever remains in the brackets will always be the same. If it's not, you've made some mistake.
So your in entirety, you equation is now
x (x + 3) -2 (x + 3)
You now move all the unbracketed terms to one side and since x + 3 is common, it will be put to the other side. Hence what you get is
(x + 3) (x - 2)
If you take each of these separately, it means that either
x + 3 = 0 or x - 2 = 0
Keeping the x on one side of the equations and moving the other components to the other side you get
x = -3 or x = 2
This my friend, is your answer :) However when writing it down you just have to write it as below.
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x^2 + x - 6
= x^2 + 3x - 2x - 6
= x (x + 3) - 2 (x + 3)
= (x + 3) (x - 2)
Hence x + 3 = 0 or x - 2 = 0
Hence x = -3 or 2
2007-12-06 22:38:56
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answer #2
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answered by M-d 2
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x^2 + x - 6 =
(x + 3)(x - 2)
2007-12-06 22:34:16
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answer #3
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answered by Johnny Handsome 2
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(x+3)(x-2)
seeing that 3 * (-2) will give you negative 6 but once you subtract 3x - 2x you still end up with a positive x
2007-12-06 22:33:58
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answer #4
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answered by Ms. Exxclusive 5
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x^2 + x -- 6
= x^2 + 3x -- 2x -- 6
= x(x + 3) -- 2(x + 3)
= (x + 3)(x -- 2)
2007-12-06 22:36:06
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answer #5
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answered by sv 7
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x^2+x-6
(x-2)(x+3)
x*x=x^2
-2*x=-2x
3*x=3x
2*-3=-6
x^2-2x+3x-6
x^2+x-6
2007-12-06 22:35:32
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answer #6
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answered by Dave aka Spider Monkey 7
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