Solution - Linear equations with one unknown
Other Ways to Solve:
Step by Step Solution
Rearrange:
Rearrange the equation by subtracting what is to the right of the equal sign from both sides of the equation :
r*r^2+48-(97)=0
Step by step solution :
Step 1 :
Trying to factor as a Difference of Cubes:
1.1 Factoring: r3-49
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 : 49 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(r) = r3-49
Polynomial Roots Calculator is a set of methods aimed at finding values of r for which F(r)=0
Rational Roots Test is one of the above mentioned tools. It would only find Rational Roots that is numbers r 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 -49.
The factor(s) are:
of the Leading Coefficient : 1
of the Trailing Constant : 1 ,7 ,49
Let us test ....
| P | Q | P/Q | F(P/Q) | Divisor | |||||
|---|---|---|---|---|---|---|---|---|---|
| -1 | 1 | -1.00 | -50.00 | ||||||
| -7 | 1 | -7.00 | -392.00 | ||||||
| -49 | 1 | -49.00 | -117698.00 | ||||||
| 1 | 1 | 1.00 | -48.00 | ||||||
| 7 | 1 | 7.00 | 294.00 | ||||||
| 49 | 1 | 49.00 | 117600.00 |
Polynomial Roots Calculator found no rational roots
Equation at the end of step 1 :
r3 - 49 = 0
Step 2 :
Solving a Single Variable Equation :
2.1 Solve : r3-49 = 0
Add 49 to both sides of the equation :
r3 = 49
When two things are equal, their cube roots are equal. Taking the cube root of the two sides of the equation we get:
r = ∛ 49
The equation has one real solution
This solution is r = ∛49 = 3.6593
One solution was found :
r = ∛49 = 3.6593How did we do?
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