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This tutorial is made to be quick and easy for anyone struggling to factoring.We’ll use a well kept secret called cross factoring to get through it. Quick and painless.
So lets begin. Here is a common example of a quadratic equation. I’ll refer to the three sets of variables as terms.
Step 1: Rewrite the equation and draw a large X under it with room on the side.
Step 2: We’ll work with x^2 first. How many x’s are there? Two obviously. So put one x on the top left and one x on the bottom left.The left side will always be where the first term goes.
Step 3: Now we’ll work with the third term, +6. Think to yourself what two numbers you could multiply to get 6. 3 and 2, or 6 and 1.
Step 4: Here is the hard part. On the side, cross multiply all four terms. x(top left) times 7, and x(bottom left) times 5 .Which set will give you the middle term, 7 (from 7x)?…Thats right, its 6 and 1. 6+1=7. You don’t need to pay attention to the x in the middle term here.
Step 5: Now just rewrite it from left to right as shown below. The answer is (x+6)(x+1)
This is called cross factoring. Its quick and easy. Check out my next lesson Factoring Harder Quadratics for idiots . Feel free to comment and subscribe for weekly updates 
Comments
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$latex 12x^2 - 5x - 2$ ?
(4x+1)(3x-2)
but w/ “cross factoring”?
Cross factoring is just another way of factoring. The answer would be the same if you factored it normally. If you mean how i got there…
12x is broken down into 4×3 or 6×2 or 12×1.
-2 is broken into -2 and 1.
So if you try 4x\/1
3x/\-2
Cross multiply that and add them,
-8+3 = -5. which is your middle number
So. (4x+1)(3x-2)
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Please define your “cross multiply” used in step 4. It looks to me like cross multiplying the 4 numbers is really just adding the elements of each column.
I was also unable to understand what purpose that big X was for; nor the two little x’s on the side.
As a final note why is this method any different from the standard “find the different ways that the constant term factors, and see which of those ways add up to the coefficient of the x-term”?
MM, in step 4, you ARE cross multiplying and adding the results. The big X is a visual aid. This method is just an alternative and if it doesn’t make it easier for you, stick to what you normally do.
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