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Exponents - Solve 3rd Degree Equation











































How would I solve for 7x^3-4x^2=3x^3-11?
Do I add the exponents together?

Comments for Exponents - Solve 3rd Degree Equation

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May 03, 2011
Solve 3rd Degree Equation
by: Staff


The question:

How would I solve for 7x^3-4x^2=3x^3-11?
Do I add the exponents together?

The answer:

No. You cannot ad the exponents together.


7x³ - 4x² = 3x³ - 11

7x³ - 3x³ - 4x² = 3x³ - 3x³ - 11

7x³ - 3x³ - 4x² = 0 - 11

7x³ - 3x³ - 4x² = - 11

4x³ - 4x² = - 11

4x³ - 4x² + 11 = - 11 + 11

4x³ - 4x² + 11 = 0

Standard form of the cubic equation

4x³ - 4x² + 11 = 0

Graphing – can find the real root by graphing

Factoring – this cubic equation cannot be factored easily. It is obvious that has complex roots.

Using the CUBIC FORMULA is the answer. It is similar to the quadratic formula, but it must be solved in steps.

Using the cubic formula is complex.

An explanation of how to use Excel to solve this problem can be down loaded here:

http://web.mit.edu/10.213/www/extra/solvecubic.pdf



The solution to your problem has 1 real root and 2 complex roots. They are:


x1=-1.13494125358
x2=1.06747062679 +j1.13293396259
x3=1.06747062679 -j1.13293396259





Thanks for writing.


Staff
www.solving-math-problems.com


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