Solution - Simplification or other simple results
Other Ways to Solve
Simplification or other simple resultsStep by Step Solution
Step 1 :
Equation at the end of step 1 :
(7x2 • x) - 8Step 2 :
Trying to factor as a Difference of Cubes:
2.1 Factoring: 7x3-8
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 : 7 is not a cube !!
Ruling : Binomial can not be factored as the difference of two perfect cubes
Polynomial Roots Calculator :
2.2 Find roots (zeroes) of : F(x) = 7x3-8
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 7 and the Trailing Constant is -8.
The factor(s) are:
of the Leading Coefficient : 1,7
of the Trailing Constant : 1 ,2 ,4 ,8
Let us test ....
| P | Q | P/Q | F(P/Q) | Divisor | |||||
|---|---|---|---|---|---|---|---|---|---|
| -1 | 1 | -1.00 | -15.00 | ||||||
| -1 | 7 | -0.14 | -8.02 | ||||||
| -2 | 1 | -2.00 | -64.00 | ||||||
| -2 | 7 | -0.29 | -8.16 | ||||||
| -4 | 1 | -4.00 | -456.00 | ||||||
| -4 | 7 | -0.57 | -9.31 | ||||||
| -8 | 1 | -8.00 | -3592.00 | ||||||
| -8 | 7 | -1.14 | -18.45 | ||||||
| 1 | 1 | 1.00 | -1.00 | ||||||
| 1 | 7 | 0.14 | -7.98 | ||||||
| 2 | 1 | 2.00 | 48.00 | ||||||
| 2 | 7 | 0.29 | -7.84 | ||||||
| 4 | 1 | 4.00 | 440.00 | ||||||
| 4 | 7 | 0.57 | -6.69 | ||||||
| 8 | 1 | 8.00 | 3576.00 | ||||||
| 8 | 7 | 1.14 | 2.45 |
Polynomial Roots Calculator found no rational roots
Final result :
7x3 - 8
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