Week 6
Substituting Variables
A variable is a letter, for example x, y or z, that represents an unspecified number.
To evaluate an algebraic expression, you have to substitute a number for each variable and perform the arithmetic operations. In the example above, the variable x is equal to 6 since 6 + 6 = 12.
If we know the value of our variables, we can replace the variables with their values and then evaluate the expression.
https://www.homeschoolmath.net/worksheets/evaluate_expressions.php
Polynomials
These are polynomials:
- 3x
- x − 2
- −6y2 − (79)x
- 3xyz + 3xy2z − 0.1xz − 200y + 0.5
- 512v5 + 99w5
- 5
(Yes, “5” is a polynomial, one term is allowed, and it can be just a constant!)
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” (see fractional exponents)
GED Program 