This is a PowerPoint on teaching the subject of Polynomials, Monomials, and Rational Expressions, dealing with how to add, subtract, multiply, and simplify all of these.
2. Monomials
An algebraic expression consisting of
one term.
Examples of a monomial :
5x^2
9ab
Not a Monomial :
2x+7
4x^2+3x-9
3. Polynomials
An expression of more than two
algebraic terms.
What makes terms not polynomials?
Cannot have a negative exponent.
Cannot have variables in the
denominator.
Cannot have variable inside a radical.
4. Polynomial or not?
1/x^2-12x+1
No
Square Root of x+3x-8
No
6x^(-3)-3x+7
No
3x^2+2x-4
YES
5. Rational Expressions
Any expression that can be written as the
ratio of two polynomial expressions.
Cannot have a denominator with :
Zero
Square Root
Examples of Rational Expressions :
1/(x-1)
Xy^2-y
6. Rational Expression or Not?
6x/(x-1)
YES
3x-2/0
No
3/14x-5
YES
4x/Square Root of 7
No
7. Adding Polynomials and
Rational Expressions
Only add if you have like terms
If you do, Add together like terms
Example :
(2x^2-3x+4) + (8x^2-4x-16) =
10x^2-7x-12
Try This One :
(X^2+6x-17)+(3x^2-9x+11) =
8. Subtracting Polynomials and
Rational Expressions
Only subtract if you have like terms
If you do, subtract like terms
Example :
(6x^2+12x+8) – (4x^2+9x+9) =
2x^2+3x-1
Try this one :
(3x^2-4x+19) – (2x^2-8x+18) =
9. Examples for you to Try
Addition :
(18x^3+x^2+3x-1) + (2x^3-3x^2+8x+3)
(8x^3+7x-9) + (9x^2-8+6x)
Subtraction :
(7x^2-2x-90) – (28x^3+20x-90)
(8x^2-7x+3) – (18x^4+44x-18)
10. Cross Multiplying and Factoring
Dealing with multiplication and division
Cross out and cancel like terms
Example : 4x/8 = x/2
Take 4 out of top and bottom
Do this until you cannot factor anymore
11. Multiplying Polynomials
If there is no denominator :
Multiply Like terms
Powers on terms are to be added
If there is a denominator :
look to cancel like terms
Look to Cancel x terms/variables
Look to factor common factors (Ex. 4/8 or
3/6)
12. Examples of Factoring and
Cross Multiplying
(8x/3)*(9x/4)
(8*x/3)*(9*x/4)
6x^2
(4x^2/10x)*(5x^2/8x^2)
(4*x*x/10*x)*(5*x*x/8*x*x)
x/4
Try this one :
(9x^2/26x)*(13/81x) =
14. Non-Factorable Multiplication
Problems
Multiplication where factoring will not
work
This means it is absolutely simplified
Check Work always to make sure
Example :
(x-2)/(7)*(3)/(x) =
3(x-2)/7x
15. Tips to Remember
Always check your work!
Always look to simplify when possible
Do not skip steps
That is where most mistakes occur
Take your time