Chapter Five — Graphing Linear Equations in Two Variables
The Humongous Book of Algebra Problems
5.30 Calculate the slope of the line that passes through points and
Substituting these values into the slope formula produces a complex fraction.
To simplify the numerator and denominator of the slope, ensure that the
fractions you combine have common denominators.
Once the numerator and denominator are rational numbers, rewrite the
fraction as a quotient and simplify.
5.31 Calculate the slope of the horizontal line y = 2.
To calculate slope using the formula m = , you need two points, (x
), on the line. Every point on the line y = 2 has a y-value of 2; no
matter what real number is used for the x-value, the point (x,2) belongs to the
horizontal line. For instance, set x
= 0 and x = 5 to get points (0,2) and (5,2) on
the graph of y = 2. Apply the slope formula.
The slope of the line y = 2 is 0.
see Problems 2.41–
over a fraction
is just a division
problem, and dividing
is the same thing
as multiplying by a
reciprocal. That’s how
Every horizontal line has slope 0. All the points on
the line have the same y-value, and when you subtract
equal y-values in the numerator of the slope formula, you get
0. Zero divided by any real number except zero will equal 0.