Give the polynomial function whose roots are -2 1 and 3

The polynomial cannot be factored in the set of Real numbers: The roots of the polynomial equation are complex.
You should use the command cFactor( found under F2:Algebra> A:Complex>2:cFactor(
However, you should set the Mode Complex>Rectangular, and the EXACT/APPROXIMATE mode to Exact, otherwise your roots will be in decimal representation.

What is the question. Your calculator FX-9750 GII does not have a Computer Algebra System or CAS, so you cannot factor a polynomial.
If you want you can try to find the zeros of the polynomial function (the values of x when the function crosses the horizontal axis) either by solving P(x)=0 or by graphing y=P(x).
Once you have the approximate roots x_1, x_2, ...,x_n, you can factor out the coefficient of the leading term (the term with the highest power) and write P(x) =a_n *G(x). here a_n is the coefficient of the leading term.
G(x) can then be written as G(x)=(x-x_1)(x-x_2)*(x=x_3)...(x-x_n)
and the original polynomial will be
P(x)=a_n(x-x_1)(x-x_2)*...*(x-x_n)
Note: Here is an example of P(x) and the corresponding G(x)
P(x)=5x^3+7x^2-13x^+29
P(x)=5(x^3+ (7/3)*x^2-(13/5)x+29/5)
G(x)=x^3+ (7/3)*x^2-(13/5)x+29/5
You should keep in mind that the roots are in general complex. Not all polynomials are factorisable in the set of Real numbers.

You can do it two ways.
Graphically:
Open the graph utility, enter a function y1= expression(x) where expression(x) is the polynomial. Graph the function y1(x). Play with the window dimensions to display the interesting part of the graph. You can then see if there are any zeros (roots).
While the graph is displayed, press SHIFT F5 (G-Solv). Press F1:Root to look for a root. Read the value of the root at the bottom of the screen (to the left).

Solve utility
Open the QEquation solver, select F2:polynomial, or F3: solver.
The polynomial solve can solve polynomial equations up to degree 6.
The solve solve polynomial and any other type of non algebraic equations

We can write this polynomial as:

• (x-(-2))*(x-1)*(x-3)=
• (x+2)(x-1)(x-3)=
• (x+2)[x*(x-3)-1*(x-3)]=
  
• (x+2)*(x^2-3x-x+3)=
• (x+2)(x^2-4x+3)=
• x*(x^2-4x+3)+2*(x^2-4x+3)=
• x^3-4x^2+3x+2x^2-8x+6=
• x^3-2x^2-5x+6

x^3-2x^2-5x+6 is polynomial with roots -2, 1, 3.

You can see this polynomial in following picture:



Notice that it intersects x axis for x=-2, 1 and 3 (because these are roots of polynomial).

One way is to use the Polynomial Root Finder and Simultaneous Equation Solver app.

Press the APPS key, then select PlySmlt2 and press ENTER. Press ENTER to get past the opening screen, then select "POLY ROOT FINDER" and press ENTER. Select the order of the polynomial and other settings as desired. Press F5 (the GRAPH key) to go to the next screen. Enter the polynomial coefficients, then press F5 to solve. The next screen will show you the roots (unless you selected real roots and the polynomial doesn't have any real roots).

If you don't have the app installed, you can download it from
http://education.ti.com/educationportal/sites/US/productDetail/us_poly_83_84.html

The short story is that this calculator does have a computer algebra system or CAS and thus cannot factor polynomials with arbitrary (unknown) coefficients or known coefficients.
However if the coefficients are given you can ,if you are willing to travel that way, factor approximately a polynomial P(x).
Basically, the idea is that any polynomial P(X) of degree n can be written in the factored form (X-x_1)(X-x_2)...(X-x_n), where x_1, x_2, x_3,...x_n are the roots (real or complex) of the equation P(X)=0.


The procedure ( for a 3rd degree polynomial) is as follows: (the fixYa site parser will remove the plus signs, so I am writing the whole word plus instead of the mathematical sign
If you want to factor a cubic polynomial P3(X) = aX^3 plus bX^2 plus cX plus d , you write the corresponding cubic equation as aX^3 plus bX^2 plus cX plus d =0 , then you divide all terms of the equation by a to obtain

X^3 plus (b/a)X^2 plus (c/a)X plus (d/a)=0.

You use the calculator to solve (approximately) this equation.
Suppose you find the 3 roots X1,X2,and X3. Then the polynomial X^3 plus (b/a)X^2 plus (c/a)X plus (d/a) can be cast in the factored form (X-X1)(X-X2)(X-X3) and the original polynomial P3(X) can be written as

P3(X) = a*(X-X1)(X-X2)(X-X3)

You can handle the quadratic polynomial the same way.
P2(X) =a*(X-X1)(X-X2) where X1, X2 are the two real roots.

To find the various roots you must use the solve( application.

The short story is that this calculator does have a computer algebra system or CAS and thus cannot factor polynomials with arbitrary (unknown) coefficients or known coefficients.
However if the coefficients are given you can ,if you are willing to travel that way, factor approximately a polynomial P(x).
Basically, the idea is that any polynomial P(X) of degree n can be written in the factored form (X-x_1)(X-x_2)...(X-x_n), where x_1, x_2, x_3,...x_n are the roots (real or complex) of the equation P(X)=0.


The procedure ( for a 3rd degree polynomial) is as follows:
If you want to factor a cubic polynomial P3(X) = aX^3 bX^2 cX d , you write the corresponding cubic equation as aX^3 bX^2 cX d =0 , then you divide all terms of the equation by a to obtain

X^3 (b/a)X^2 (c/a)X (d/a)=0.

You use the calculator to solve (approximately) this equation.
Suppose you find the 3 roots X1,X2,and X3. Then the polynomial X^3 (b/a)X^2 (c/a)X (d/a) can be cast in the factored form (X-X1)(X-X2)(X-X3) and the original polynomial P3(X) can be written as

P3(X) = a*(X-X1)(X-X2)(X-X3)

You can handle the quadratic polynomial the same way.
P2(X) =a*(X-X1)(X-X2) where X1, X2 are the two real roots.

Hello,

Sorry, but what you wrote is not an equation but a polynomial expression. You want to solve the equation x^4+5x^3-3x^2-43x-60 =0.

The solve( command, can only be used with real numbers.
The solve( is available through the CATALOG : [2nd][CATALOG], scroll down till you reach the command. Highlight it and press [ENTER]. The command echodes on main screen as solve( .
You complete the command by entering the expression (not the equation), the name of the variable you solve for, the initial guess , and { lower limit, upper limit} between curly brackets, and the closing parenthesis.
Exemple:
solve (x^4+5x^3-3x^2-43x-60 , x,0 {-5,0} ) [ENTER]
should give you the negative root,
solve (x^4+5x^3-3x^2-43x-60 , x,0 {0,5} ) [ENTER]
should give you the positive root.

It is implied that the expression is 0, so you should not insert =0, otherwise you get an error. Here for the lower limit is -5 you must use the change sign symbol (-) under the 3 key, not the regular MINUS.

You may ask how I knew that there were two roots when the equation is a quartic? By first graphing it to have an idea about where the roots lie and how many there are. You should always do that to speed up the search.

There is another way to zoom in on the roots: by drawing the graph and using the tools accessible under the [2nd][CALC] menu, namely the option [2:Zero]
The resolution of the TI83/84 is not good enough for this function that grows too fast, but I am inserting a picture of the curve from another calculator with a much better resolution.



Hope it helps.

Hello,
Sorry, but you cannot use this calculator to factorize a general polynomial.
1. It does not know symbolic algebra.
2. It can only manipulate numbers.

However if you have polynomials of degree 2 or 3, with numerical coefficients (no letters) you can set [MODE] to equation and use the equation solver to find the real roots of 2nd degree or 3rd degree polynomials. Assuming that your polynomials have real roots (X1, X2) for the polynomial of degree 2, or (X1, X2, X3) for the polynomial of degree 3, then it is possible to write
P2(X) =a*(X-X1)(X-X2)
P3(X)= a(X-X1)(X-X2)(X-X3)
This is an approximate factorization, except if your calculator configured in MathIO, has been able to find exact roots (fractions and radicals)
where a is the coefficient of the highest degree monomial aX^2 +...
or aX^3 +....

But I have a hunch that this is not what you wanted to hear.

Good luck.

Hello,
Sorry, but you cannot use this calculator to factor a general polynomial.
1. It does not know symbolic algebra.
2. It can only manipulate numbers.

However if you have polynomials of degree 2 or 3, with numerical coefficients (no letters) you can set [MODE] to Equation and use the equation solver to find the real roots of 2nd degree or 3rd degree polynomials. Assuming that your polynomials have real roots (X1, X2) for the polynomial of degree 2, or (X1, X2, X3) for the polynomial of degree 3, then it is possible to write

P2(X) =a*(X-X1)(X-X2)
P3(X)= a(X-X1)(X-X2)(X-X3)

where a is the coefficient of the highest degree monomial aX^2 +...
or aX^3 +....

This is an approximate factorization, except if your calculator configured in MathIO, has been able to find exact roots (fractions and radicals)

While the [MODE][5:Equation] only handles quadratic and cubic equations, the [SHIFT][SOLVE=] solver finds the roots of arbitarry expressions (not limited to polynomials). In principle you can use it to find the roots of an expression. If it is a polynomial of dgree higher that 3 you can factor it (approximately).

But I have a hunch that this is not what you wanted to hear.

Hope it helps.