You will have 5 minutes to solve each equation you are given for the
variable y and simplify the result.
A prize will be awarded to all students who solve at least 4 out of 5
All of your work must be shown to receive credit and the problems and
work must be neatly numbered & organized in your notes. Put a circle or
box around your final answer for each problem.
Equations of Lines (Sec. 4.6)
Slope and Lines Consider the points graphed below. Copy this to your notes.
If m(A, B) = 1 and C and D are collinear with A and B,
what is m(C, D)?
Key Idea: The slope through two points on a line isn't
just for those two points...it's for the entire line!
TOPIC ONE Think back: What does an equation for a line look like?
of Lines: (Ex. #1)
We are going to use our slope formula to help us find the
equation of a line. Copy the info below into your notes.
A(5, 4) B(‐1, 1)
Step #1: Find the slope of the line we want the equation of.
(Think back: The slope of the line is always the same as
Step #2: Introduce variables to represent other points
on that line.
Step #3: Find the slope between an original point on the line
and our variable point.
(Think back: What does that slope need to equal?)
Step #4: Simplify your equation by solving for y.
Finding Equations We want to find the equation of a line that passes through
of Lines: (Ex. #2) G(2, 8) and H(6, 0).
Finding Equations Find the equation of a line through M(‐9, ‐1) and N(3, 7).
of Lines: (Ex. #3) Please label each step in your work.
It's your turn! Step #1 Result:
Step #2 Result:
Step #3 Result:
Step #4 Result:
Think back: Why does this give us the equation of the line?
TOPIC TWO If we have the equation of a line like 2x + y = 5, how can
Finding Slope from we find the slope of the line?
an equation: (Ex. #1)
Think back: How do we typically find slope?
Finding Slope from Given the equation y ‐ 8 = .75(x + 4), what is the slope of the
an equation: (Ex. #2) line?
Finding Slope from You have the equation y = ‐3x + 7. What is the slope of this
an equation: (Ex. #3) line?
It's your turn!
Exit Slip: Please complete the exit slip handed out with your
partners. It will count as a class grade for today. Refer to
each other and your notes as you answer the problems.
Your work should reflect what we did in class today. In
other words, make sure that you show work like we did in
When you finish the exit slip, please start your assignment.
You should be busy with math until the bell rings. If you
need help once you start the assignment, check with your
partner first. If you're both stuck, I will be more than happy
to assist you!