kayduit wrote:
Hello Everyone,
I understand factoring and the theory behind it. However, I have issues coming up with the factorisations myself. Once I see an answer i can work towards it, but doing it myself is impossible. I don't know what the steps are that people take. In the official GMAT guide for example this problem is shown:
Step 1: 3x2 −3=8x
Step 2: 3x2 −8x−3=0
Step 3: (3x + 1)(x − 3) = 0
Step 4: 3x + 1 = 0 or x − 3 = 0
Step 5: x = − 13 o r x = 3
I understand how they go from step 2 to 3, but I would never be able to think of that myself. is there an easy way of coming up with this?
Don't worry if you're unable to factories it that way.
Fortunately, we have an alternative and better approach for Quadratic equations of form ax²+bx+c=0
Use Quadratic formula to get roots directly.
Formula is ;
X = [-b±(b²-4ac)^½]/2a
Even if you want to factories only, than also you can use this formula. For example, if you get x=1,2 with this formula, then the factors will be (x-1)(x-2).
You can use this formula in other situations too.
Let me know if the answer was helpful.
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