3.5 – Write and Graph
Equations of Lines
Linear equations may be written in different
forms. The general form of a linear equation
in slope-intercept form y = mx+b, where m
is the slope and b is the y-intercept.
3.5 – Write and Graph
Equations of Lines
Example 1:
Write an equation of the line in slopeintercept form.
3.5 – Write and Graph
Equations of Lines
Example 2:
Write an equation of the line in slopeintercept form.
3.5 – Write and Graph
Equations of Lines
Example 3:
Write an equation of the line passing through
the point (-1, 1) that is parallel to the line with
the equation y = 2x – 3.
3.5 – Write and Graph
Equations of Lines
Example 4:
Write an equation of the line passing through
the point (2, -3) that is parallel to the line with
the equation y = 6x +4.
3.5 – Write and Graph
Equations of Lines
Example 5:
Write an equation of the line passing through
the point (2, 3) that is perpendicular to the
line with the equation y = -2x + 2.
3.5 – Write and Graph
Equations of Lines
Example 6:
Write an equation of the line passing through
the point (3, -4) that is perpendicular to the
line with the equation y = -1/2x - 1
3.5 – Write and Graph
Equations of Lines
Example 7:
The graph models the total cost of joining a
gym. Write an equation fo the line. Explain
the meaning of the slope and the y-intercept
of the line.
3.5 – Write and Graph
Equations of Lines
Example 8:
The graph shows the cost of having cable
television installed in your home. Write an
equation of the line. Explain the meaning of
the slope and y-intercept of the line.
3.5 – Write and Graph
Equations of Lines
Another form of a linear equation is standard
form. In standard form, the equation is
written as Ax + By = C, where A and B are
not both zero.
3.5 – Write and Graph
Equations of Lines
Example 9:
Graph 3x + 4y = 12
3.5 – Write and Graph
Equations of Lines
Example 10:
Graph 2x – 3y = -12
3.5 – Write and Graph
Equations of Lines
Example 11:
Graph 2(x-1) =-y
3.5 – Write and Graph
Equations of Lines
Example 11:
Graph x – 3 = 0
3.5 – Write and Graph
Equations of Lines
Example 12:
Graph y +3 = 2
3.5 – Write and Graph
Equations of Lines
Example 13:
Graph 2y – 4 = 2x
3.5 – Write and Graph
Equations of Lines
Example 11:
You can rent DVD’s at a local store for $4.00
each. An Internet company offers a flat fee of
$15.00 per month for as many rentals as you
want. How many DVD’s do you need to rent
to make the online rental a better buy?
3.5 – Write and Graph
Equations of Lines
Example 12:
One bank charges $1.50 for each use of its
debit card. Another bank charges $10 per
month for an unlimited number of debit card
uses. How many times per month would you
need to use your debit card to make the bank
that charges a flat rate the better choice?