Quadratic Factoring Flashcards
Simple Trinomial
A trinomial with a leading coefficient of 1
1x²+bx+c which is the same as x²+bx+c
Complex Trinomial
A trinomial with a leading coefficient other than 1
a is not 1 for ax²+bx+c
Special Binomial
There are 3, but we have only studied 1 called…
Difference of Squares, i.e.,
x² - 4
9y² - 36
A perfect square minus a constant
To factor a Simple Trinomial
When a is 1
Find 2 magic numbers, such that
they multiply to the constant term
and add to the x term
mn=c and m+n=b if x²+bx+c factors to (x+m)(x+n)
To factor a Difference of Squares
A perfect square minus a constant
Find the root of both terms,
then write as two factors: a difference and a sum
(a²x²-b²) = (ax - b)(ax + b)
To factor a Complex Trinomial
When a is not 1
Use the box method…
Column 1: 2 terms that multiply to give the leading term
Column 2: 2 numbers that multiply to give the constant term
Check: cross multiply the box and then add and compare to the x term
If the Check passes: Read your Factors from the Rows of the box
If the Box method fails…
i.e., If cross multiplying the box and adding doesn’t equal the x term
- Try swapping the order for Column 2
- Try different numbers for Column 2
- Try different terms for Column 1
- Consider all possible multiples, including 1
- Check the Discriminant
The discriminant (b² - 4ac) needs to be 0 or a perfect square to use Box
The first step of factoring is always…
Check for and factor out Common Factors
The last step of factoring is always…
Check each factor to ensure they can’t be further factored