january 21, 2015

21

Warm-Up Khan Academy Practice

Point-Slope Form Interpreting Intercepts

Class Work Begin Parallel & Perpendicular Lines

Tomorrow

Today:

Warm-Up1. - -3(8) -2 + -(4)

3. Find the length & width:

2x + 10

x P = 68

2. Solve for x: rx + 9 = h 5

x = 5h -9 r

4. Solve: 2y + 2 < 11+ 3 < 8 + y5. 1 pounds of peanuts were divided equally amongst 3 friends. What was the weight of peanuts each friend received?

Interpreting Linear Functions

and Finding Intercepts

Khan Academy

elevation = 12

kilometers

Draw a graph!

Draw a graph!

12 hours

Linear Equations• Linear Equations form straight lines. How

do we determine if an equation is linear? It can be rewritten in the form: Ax + By = C This is the Standard Form of a linear equation where:

a.) A and B are not both zero. b.) The largest exponent is not greater than 1

Determine Whether the Equations are Linear: 1. 4 - 2y = 6x 2. -4/5x = -2 3. -6y + x =

5y - 2Remember:

This is to determine whether an equation is linear (forms a straight line) or not. The standard form is also used to determine x and y intercepts.

Practice Questions:

1. From the table, determine the function, fill in the missing values, and write the equation solving for y. f(x) =

Find the missing coordinate of a line with

points (–2, R) and (4, 6) and a slope of32

Practice Questions:

If (a,2) is a point on the graph of 2x - 7y =

20, what is a?

R = -3

When to use the point-slope form of a line:a. If all you have to work with is one

point on the line and the slope of the line

b. If all you have are two points on the line

Write the equation of a line passing through

the point (2,5) with a slope of -2

Practice Questions:Write the standard form for the equation of

the line through the point (-2, 5) with a slope of 3.

Use the point-slope form, y – y1 = m(x – x1), with m = 3 and (x1, y1) = (-2, 5). y – y1 = m(x – x1) Point-slope form

y – y1 = 3(x – x1) Let m = 3.

y – 5 = 3(x – (-2)) Let (x1, y1) = (-2, 5).

y – 5 = 3(x + 2) Simplify.

y = 3x + 11 Slope-intercept form

3x – y = - 11 Standard Form

Practice Questions:Example: Write the equation of the line

through the points (4, 3) and (-2, 5).

y – y1 = m(x – x1) Point-slope form

Slope-intercept formy = - x + 13

31

3

2 1 5 – 3 -2 – 4

= - 6

= - 3

Calculate the slope.m =

Use m = - and the point (4, 3).y – 3 = - (x – 4)1

3 3

1

Find the x-intercept of the line with slope of 2 and passing through the points (-1,

2) and (0,4)

Find the equation of the line that has a slope of and a y-intercept of -1. Graph the line and write the equation in both slope-intercept and standard forms with integers only for the standard form.

The only information you have is the slope , and a point on the line, (1,2). Use the correct equation & graph the line. Then write the equation in standard

form with integers only.

You begin with the point-slope formula, which becomes the slope-intercept form. Use the slope-intercept to graph.

To put the equation in

standard form, you can do this...

What if:

Practice Problems

Practice ProblemsStandard Form,

No fractions

1. A line with the equation: y = 2x -5 will never touch what quadrant of the coordinate plane?2. A line with the equation: -3x – y = 6 will

never touch what quadrant of the coordinate plane?

Practice Problems

3. Which graph shows the finish line of a one mile race between 2 Olympic runners? Who won?

x

y

What is the equation of the line shown?

Practice Problems

y = x + 2

1. Is the graph a function? Why or why

not?

2. Is the graph a linear function? Why or why not?

3. What is the per week rate of

change between weeks 1-3?

4. What is the per week rate of change between

weeks 6-10?

Practice Problems

Class Work 2.12;

Show All Work

Practice Problems: