polynomials. what is a polynomial? an algebraic expression that contains more than two terms...
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POLYNOMIALS
WHAT IS A POLYNOMIAL?
An algebraic expression that contains more than two terms
Polynomial literally means poly – (meaning many) and nomial - (meaning terms). Or in this case, many terms.
DEFINITIONS Variable: a symbol for a number we don’t know yet. In math, we will usually represent this using ‘x’ or ‘y’
Term: a single number or variable, or a combination of both.
Algebraic Expression: a mathematical phrase that contains terms and operations.
Constant: a term that is a number. It is not changing.
Exponent: Like the 2 in y². But for the purposes of polynomials, they can only be 0, 1, 2, 3, etc
EXAMPLES OF POLYNOMIALS
2x + 3
4xᶾ – 3x + 7
9y⁸ + 14y⁴ – 3z
TYPES OF ALGEBRAIC EXPRESSIONS Monomial
Binomial
Trinomial
Polynomial
MONOMIAL
Containing only one term
Examples: x, y, 3, 4rᶾ, 7m⁸, 2xyᶾ
BINOMIAL
Containing two terms
Examples: 2x + 3, 9y – 1, r² + 5, x²v⁴ + c
Where do we see binomials?
TRINOMIAL
Containing three terms
Examples: 2xy + 4z – t, ax² + bx +c, 3 + 4mn – 7oᶾ
Where do we see trinomials?
POLYNOMIAL
Containing more than three terms
We will use the term polynomial to classify all expressions with two or more terms as stated previously
More specifically, we will use it for four or more terms
THINK BICYCLES!!!!
We can combine polynomials using addition, subtraction, multiplication, and division
Whenever we combine polynomials, we get back polynomials. This is what makes them so special and easy to work with!
NOTE: We cannot divide by a variable in a polynomial. (So 2/x is NOT a polynomial)
THESE ARE POLYNOMIALS•3x
•x - 2
•-6y2 - (7/9)x
•3xyz + 3xy2z - 0.1xz - 200y + 0.5
•512v5+ 99w5
•5
THESE ARE NOT POLYNOMIALS•3xy-2 is not, because the exponent is "-2" (exponents can only be 0,1,2,...) •2/(x+2) is not, because dividing by a variable is not allowed
•1/x is not either
•√x is not, because the exponent is "½"
BUT THESE ARE
x/2 is allowed, because you can divide by a constant
3x/8 for the same reason
√2 is allowed, because it is a constant (= 1.4142...etc)
DEGREE
We can classify polynomials by degree.
This is the highest exponent in a polynomial.
Example: 4xᶾ -2x +1 has degree 3
What is the degree of x²y²?
What is the degree of m⁴n?
What is the degree of abᶾd⁵?
Example: What is the degree of this polynomial?
4z3 + 5y2z2 + 2yz
Checking each term:
4z3 has a degree of 3 (z has an exponent of 3)
5y2z2 has a degree of 4 (y has an exponent of 2, z has 2, and 2+2=4)
2yz has a degree of 2 (y has an exponent of 1, z has 1, and 1+1=2)
The largest degree of those is 4, so the polynomial has a degree of 4
STANDARD FORM
When writing a polynomial in standard form, we put the terms with the highest degree first
3x² - 2 + 7x⁸ - 5xᶾ would be written as 7x⁸ - 5xᶾ + 3x² - 2
LIKE TERMS
Like terms are terms who have the same variable AND exponent
3x – 5x
2yz + 8yz
7z – 9z
3x² + 2x²
5rs⁴ - 3rs⁴
2mn⁸ + 5mn⁸ - 11mn⁸
xy + 3xy – 9xy + 4xy – 2xy
In all of the previous examples, we can collect the ‘like terms’ to reduce all of our expressions
Let’s try!
3x – 5x
2yz + 8yz
7z – 9z
3x² + 2x²
5rs⁴ - 3rs⁴
2mn⁸ + 5mn⁸ - 11mn⁸
xy + 3xy – 9xy + 4xy – 2xy
If the terms are unlike terms, we cannot collect them.
x² + xᶾ x⁵
TODAY WE WILL LOOK AT ADDING
AND SUBTRACTING POLYNOMIALS
ADDITION
3x + 2 and 4x + 1
ADDITION
4x – 8yz and 7x – 3yz
ADDITION
-x² + 3 and 2x + 1
ADDITION
4xy² - 3x + 8 and -7xy² +5x
SUBTRACTION
x + 7st and x – 9st
SUBTRACTION
3x + 4x²y and -5x – 6x²y
SUBTRACTION
-3yzᶾ -6x⁴z² + yz + 1 and -4yzᶾ +2x⁴z² + yz - 5
SUBTRACTION
6b²c + y + b and 6b²c +2y² - b
SIMPLIFY THE FOLLOWING EXPRESSIONS 8x + 2y – z + 2x – 6y + 4
3st² – 5s – 6st² +7s + tᶾ
YOUR TURN!!!!
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