A polynomial is an expression consisting of variables and coefficients, that involves only the operations of addition, subtraction, multiplication, and non-negative integer exponents of variables.
P(x)=anxn+an−1xn−1+⋯+a1x+a0
Here, x is the variable, ai are the coefficients, and n is a non-negative integer representing the degree of the polynomial.
• Terms: Each part of the polynomial separated by addition or subtraction is a term. For example, in 3x2+2x−5, the terms are 3x2, 2x, and −5.
• Degree: The highest exponent of the variable in a polynomial is its degree. For 3x2+2x−5, the degree is 2.
• Monomial: A polynomial with one term (e.g., 5x3).
• Binomial: A polynomial with two terms (e.g., x+2).
• Trinomial: A polynomial with three terms (e.g., x2−3x+1).
Operations with Polynomials:
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Addition/Subtraction: Combine like terms (terms with the same variable and exponent).
Example: (2x2+3x−1)+(x2−x+4)=(2x2+x2)+(3x−x)+(−1+4)=3x2+2x+3.
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Multiplication: Use the distributive property. Multiply each term in the first polynomial by each term in the second.
Example: (x+2)(x−3)=x(x−3)+2(x−3)=x2−3x+2x−6=x2−x−6.
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Division: Can be done using polynomial long division or synthetic division.
Factoring Polynomials:
This is the reverse of multiplication. It involves finding polynomials that multiply together to give the original polynomial. Common methods include:
• Factoring out the greatest common factor (GCF).
• Factoring quadratics (e.g., x2+bx+c).
• Difference of squares (a2−b2=(a−b)(a+b)).
• Sum/Difference of cubes (a3±b3).