Solution - Factoring binomials using the difference of squares
Step by Step Solution
Step 1 :
9
Simplify ——————
x3 + 9
Trying to factor as a Sum of Cubes :
1.1 Factoring: x3 + 9
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 : 9 is not a cube !!
Ruling : Binomial can not be factored as the difference of two perfect cubes
Polynomial Roots Calculator :
1.2 Find roots (zeroes) of : F(x) = x3 + 9
Polynomial Roots Calculator is a set of methods aimed at finding values of x for which F(x)=0
Rational Roots Test is one of the above mentioned tools. It would only find Rational Roots that is numbers x which can be expressed as the quotient of two integers
The Rational Root Theorem states that if a polynomial zeroes for a rational number P/Q then P is a factor of the Trailing Constant and Q is a factor of the Leading Coefficient
In this case, the Leading Coefficient is 1 and the Trailing Constant is 9.
The factor(s) are:
of the Leading Coefficient : 1
of the Trailing Constant : 1 ,3 ,9
Let us test ....
P | Q | P/Q | F(P/Q) | Divisor | |||||
---|---|---|---|---|---|---|---|---|---|
-1 | 1 | -1.00 | 8.00 | ||||||
-3 | 1 | -3.00 | -18.00 | ||||||
-9 | 1 | -9.00 | -720.00 | ||||||
1 | 1 | 1.00 | 10.00 | ||||||
3 | 1 | 3.00 | 36.00 | ||||||
9 | 1 | 9.00 | 738.00 |
Polynomial Roots Calculator found no rational roots
Equation at the end of step 1 :
d 9
—— • ——————
dx x3 + 9
Step 2 :
d
Simplify ——
dx
Canceling Out :
2.1 Canceling out d as it appears on both sides of the fraction line
Equation at the end of step 2 :
1 9
— • ——————
x x3 + 9
Step 3 :
Trying to factor as a Sum of Cubes :
3.1 Factoring: x3+9
Check : 9 is not a cube !!
Ruling : Binomial can not be factored as the difference of two perfect cubes
Trying to factor as a Sum of Cubes :
3.2 Factoring: x3+9
Check : 9 is not a cube !!
Ruling : Binomial can not be factored as the difference of two perfect cubes
Final result :
9
————————————
x • (x3 + 9)
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