If you have both equations in the same format, then if the
coefficients for the variable(s) are the same, then the lines are
parallel. To take a simple example, linear equations in beginning
algebra are often put in the form:
y = m*x + b
Where m and b are each actual numbers (the slope and y-intercept,
respectively), x is the independent variable and y is the dependent
variable. If you have two linear equations of this form (or you can
get them into this form), and the 'm' is the same in each equation,
then the lines are parallel.
If there are multiple independent variables, for example:
z = m*x + n*y + b
Then you need to make sure that each coefficient (in this case, m and
n) is the same in one equation as it is in the other.
If my explanation is unclear, you may find this site, which has
diagrams and things, and was presumably written by a professional
educator, more clear:
http://www.wtamu.edu/academic/anns/mps/math/mathlab/int_algebra/int_alg_tut15_slope.htm |
