Solution - Factoring binomials using the difference of squares
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Factoring binomials using the difference of squaresStep by Step Solution
Step 1 :
Trying to factor as a Difference of Squares :
1.1 Factoring: x30-36
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 : 36 is the square of 6
Check : x30 is the square of x15
Factorization is : (x15 + 6) • (x15 - 6)
Trying to factor as a Sum of Cubes :
1.2 Factoring: x15 + 6
Theory : A sum of two perfect cubes, a3 + b3 can be factored into :
(a+b) • (a2-ab+b2)
Proof : (a+b) • (a2-ab+b2) =
a3-a2b+ab2+ba2-b2a+b3 =
a3+(a2b-ba2)+(ab2-b2a)+b3=
a3+0+0+b3=
a3+b3
Check : 6 is not a cube !!
Ruling : Binomial can not be factored as the difference of two perfect cubes
Trying to factor as a Difference of Cubes:
1.3 Factoring: x15 - 6
Theory : A difference of two perfect cubes, a3 - b3 can be factored into
(a-b) • (a2 +ab +b2)
Proof : (a-b)•(a2+ab+b2) =
a3+a2b+ab2-ba2-b2a-b3 =
a3+(a2b-ba2)+(ab2-b2a)-b3 =
a3+0+0-b3 =
a3-b3
Check : 6 is not a cube !!
Ruling : Binomial can not be factored as the difference of two perfect cubes
Final result :
(x15 + 6) • (x15 - 6)
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