Step-by-step explanation:
STEP 1:
The equation at the end of step 1
STEP 2:
The equation at the end of step 2:
STEP 3:
STEP 4: Pulling out like terms
4.1 Pull out like factors:
Trying to factor by splitting the middle term
4.2 Factoring 
The first term is, 
its coefficient is 1.
The middle term is, 
its coefficient is -2.
The last term, "the constant", is +1.
Step-1: Multiply the coefficient of the first term by the constant 1 • 1 = 1
Step-2: Find two factors of 1 whose sum equals the coefficient of the middle term, which is -2.
-1 + -1 = -2 That's it
Step-3: Rewrite the polynomial splitting the middle term using the two factors found in step 2 above, -1 and -1
x4 - 1x2 - 1x2 - 1
Step-4 : Add up the first 2 terms, pulling out like factors :
x2 • (x2-1)
Add up the last 2 terms, pulling out common factors :
1 • (x2-1)
Step-5 : Add up the four terms of step 4 :
(x2-1) • (x2-1)
Which is the desired factorization
Trying to factor as a Difference of Squares:
4.3 Factoring: x2-1
Theory : A difference of two perfect squares, A2 - B2 can be factored into (A+B) • (A-B)
Proof : (A+B) • (A-B) =
A2 - AB + BA - B2 =
A2 - AB + AB - B2 =
A2 - B2
Note : AB = BA is the commutative property of multiplication.
Note : - AB + AB equals zero and is therefore eliminated from the expression.
Check : 1 is the square of 1
Check : x2 is the square of x1
Factorization is : (x + 1) • (x - 1)
Trying to factor as a Difference of Squares:
4.4 Factoring: x2 - 1
Check : 1 is the square of 1
Check : x2 is the square of x1
Factorization is : (x + 1) • (x - 1)
Multiplying Exponential Expressions:
4.5 Multiply (x + 1) by (x + 1)
The rule says : To multiply exponential expressions which have the same base, add up their exponents.
In our case, the common base is (x+1) and the exponents are :
1 , as (x+1) is the same number as (x+1)1
and 1 , as (x+1) is the same number as (x+1)1
The product is therefore, (x+1)(1+1) = (x+1)2
Multiplying Exponential Expressions:
4.6 Multiply (x-1) by (x-1)
The rule says : To multiply exponential expressions which have the same base, add up their exponents.
In our case, the common base is (x-1) and the exponents are :
1 , as (x-1) is the same number as (x-1)1
and 1 , as (x-1) is the same number as (x-1)1
The product is therefore, (x-1)(1+1) = (x-1)2
Final result :
4 • (x + 1)2 • (x - 1)2
