
Here we will show you how to factor the quadratic function x² + 10x + 24 using the box method. In other words, we will show you how to factor x squared plus 10x plus 24 (x^2 + 10x + 24) 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 x² + 10x + 24, like this:
a = 1
b = 10
c = 24
Step 2: Next, we need to draw a box and divide it into four squares:
4 | 4x | 24 |
x | x² | 6x |
x | 6 |
4 | 4x | 24 |
x | x² | 6x |
x | 6 |
More specifically, 1 times 24 is 24. Therefore, we need to find the two numbers that multiply to equal 24, and add to equal 10.
? × ? = 24
? + ? = 10
After looking at this problem, we can see that the two numbers that multiply together to equal 24, and add together to equal 10, are 4 and 6, as illustrated here:
4 × 6 = 24
4 + 6 = 10
Now, we can fill in the last two squares in our box with 4x and 6x. Place 4x in the upper left square, and place 6x in the lower right square.
4 | 4x | 24 |
x | x² | 6x |
x | 6 |
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 4x and 24. The greatest common factor of 4x and 24 is 4. Therefore, we write 4 to the left of the top row. You can see it here in the color green:
4 | 4x | 24 |
x | x² | 6x |
x | 6 |
4 | 4x | 24 |
x | x² | 6x |
x | 6 |
x² ÷ x = x
You can see this value colored in orange below:
4 | 4x | 24 |
x | x² | 6x |
x | 6 |
Next, we divide 6x by x (labeled in blue). This gives us 6.
6x ÷ x = 6
You can see this value colored in purple below:
4 | 4x | 24 |
x | x² | 6x |
x | 6 |
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 x² + 10x + 24. 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:
(x + 4)(x + 6)
That’s it! Now you know how to factor the equation x² + 10x + 24.
Factoring Quadratics
Go here if you want to learn how to factor another quadratic function.
Factor x² + 10x + 25
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