Factor 12x² + 56x

Factor 12x² + 56x - 55

Here we will show you how to factor the quadratic function 12x² + 56x - 55 using the box method. In other words, we will show you how to factor 12x squared plus 56x minus 55 (12x^2 + 56x - 55) using the box method. It is a 5-step process:

Step 1: The standard form of a quadratic equation is ax² + bx + c. We start by labeling the different parts of our equation 12x² + 56x - 55, like this:

a = 12
b = 56
c = -55

Step 2: Next, we need to draw a box and divide it into four squares:

-5	-10x	-55
6x	12x²	66x
	2x	11

We put 12x² (a) in the bottom left square and -55 (c) in the top right square, like this:

-5	-10x	-55
6x	12x²	66x
	2x	11

Step 3: In order to fill in the other two squares, we need to do some math. We have to find two numbers that multiply together to give us the product of 12 times -55 (a × c), and add together to equal 56 (b).

More specifically, 12 times -55 is -660. Therefore, we need to find the two numbers that multiply to equal -660, and add to equal 56.

? × ? = -660
? + ? = 56

After looking at this problem, we can see that the two numbers that multiply together to equal -660, and add together to equal 56, are -10 and 66, as illustrated here:

-10 × 66 = -660
-10 + 66 = 56

Now, we can fill in the last two squares in our box with -10x and 66x. Place -10x in the upper left square, and place 66x in the lower right square.

-5	-10x	-55
6x	12x²	66x
	2x	11

Step 4: Next, we need to find four final numbers to finish factoring our equation. We can see that our box is a 2 x 2 table made up of rows and columns.

Our goal is to find the numbers that, when multiplied together, result in the products in each square. We can do this by finding the greatest common factor in each row.

Let’s look at the top row. We have the terms -10x and -55. The greatest common factor of -10x and -55 is -5. Therefore, we write -5 to the left of the top row. You can see it here in the color green:

-5	-10x	-55
6x	12x²	66x
	2x	11

Next, let’s look at the bottom row. We have the terms 12x² and 66x. The greatest common factor of 12x² and 66x is 6x. Therefore, we write 6x to the left of the bottom row. You can see it here in the color blue:

-5	-10x	-55
6x	12x²	66x
	2x	11

To find the values below the table, we first divide 12x² by 6x (labeled in blue). This gives us 2x.

12x² ÷ 6x = 2x

You can see this value colored in orange below:

-5	-10x	-55
6x	12x²	66x
	2x	11

Next, we divide 66x by 6x (labeled in blue). This gives us 11.

66x ÷ 6x = 11

You can see this value colored in purple below:

-5	-10x	-55
6x	12x²	66x
	2x	11

Step 5: Now we have all of the information we need to finish factoring the equation. The values outside of the box are used to factor 12x² + 56x - 55. You simply put the values on the left in one set of parentheses, and the values below in another set of parentheses, to get the answer:

(6x - 5)(2x + 11)

That’s it! Now you know how to factor the equation 12x² + 56x - 55.

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