Graph 5X + 4Y = 8 by Completing the Following Table of Values

Standard Form

P re - R e q ui si te 8.EE.5 Graph proportional relationships, interpreting the unit rate as the slope of the St graph. Compare two different proportional relationships represented in different a ways. n d 8.EE.6 Use similar triangles to explain why the slope m is the same between any two ar distinct points on a non-vertical line in the coordinate plane, derive the equation d y=mx for a line through the origin and the equation y = mx + b of a line intercepting the vertical axis at b. C 8.4.19 - 21 C 8.2.23 L e ss o n St  Students graph linear equations on the coordinate plane. u  Students write the equation of a line given two points or the slope and a point on d the line. e n  Students know the traditional forms of the slope formula and slope-intercept t equation. L e ar ni n g G o al M e di a Standard Form

H #65 W Spiral Review #19 W K S P Standard Form

Graph 5x + 4y = 8 by completing the following table of values. x 5x + 4y = 8 y

Solution

Use x = 2 and x = -2 to find two solutions to the equation 5x + 4y = 8.

Is the point (4, 3) on the line?

Is the point (4, -3) on the line? Standard Form

Intercepts

The y-axis occurs at x = 0. Hence, to find the y-intercept of a linear equation, substitute the x with 0.

Find the y-intercept of 5x + 4y = 8.

The graph of 5x + 4y = 8 will cross the y-axis at ___.

The x-axis occurs at y = 0. Hence, to find the x-intercept of a linear equation, substitute the y with 0.

Find the x-intercept of 5x + 4y = 8.

The graph of 5x + 4y = 8 will cross the x-axis at ___. Standard Form

Exercise: Graph the following equations by using their intercepts.

1 x + y = 4 2. -3x + 8y = 24 . x-intercept: (___, 0) x-intercept:

y-intercept: (0, ___) y-intercept:

3 x – 3y = 9 4. -3x - 7y = 21 . x-intercept: x-intercept:

y-intercept: y-intercept: Standard Form

Write the Equation

We’ve learned how to write an equation of a graph in slope-intercept form.

We can now transform the slope-intercept form of an equation into standard form.

Slope-Intercept form Standard form y = mx + b ax + by = c

Exercise: Write the equation that represents the following.

1 slope-intercept form: . standard form:

2 m = -2 and (0, 3) slope-intercept form: . standard form: Standard Form

Sometimes you’ll have the blast the equation with a common denominator to get integer coefficients for x and y.

3. m = and (0, -7) slope-intercept form:

standard form:

4. (0, 4) and (5, 6) slope-intercept form:

standard form: Standard Form

Remember, the y and the x can be substituted by any point on the line.

5 (-7, 1) and (4, 0) slope-intercept form: .

standard form:

6 (-4, 5) and (2, 3) slope-intercept form: .

standard form: Standard Form

Name: ______Date: ______Pre-Algebra Exit Ticket

Graph the equation y = x – 10 using the y-intercept and slope.

Graph the equation 5x – 4y = 40 using intercepts.

What can you conclude about the equations y = x – 10 and 5x – 4y = 40? Standard Form

Name: ______Date: _____ Pre-Algebra HW #65

1. Graph x + 3y = 9 by using it’s intercepts.

Review: 2 Find the equation of the following graph. .

3 Last summer, a family took a trip to a beach that was about 200 miles away from . their home. The graph below shows the distance driven, in miles, and the time, in hours, taken for the trip. Standard Form

What was their average speed from hour 1 to hour 4? A. 25 miles per hour B. miles per hour C. miles per hour D. 100 miles per hour