Page 133 - Math Course 3 (Book 1)

Slope-Intercept Form Equations

Step 2 4y –5x + 8
The line crosses the y-axis at (0, –3). 4 = 4 Divide each side by 4.
So, the y-intercept is –3.
4y = –5x + 8 Divide each term in the
Step 3 Finally, write the equation. 4 4 4 numerator by 4.

5
y = mx + b Slope-intercept form Step 2 The y-intercept of y = – x + 2 is 2.
y = 2x – 3 Simplify. So graph (0, 2). 4

Answer The equation of the lines is
y = 2x – 3.

Graph Equations

Examples –5
Step 3 The slope is
4
Graph y = 0.5x – 7. From (0, 2), move down 5 units and right
4 units. Draw a dot.
Step 1 The y-intercept is –7.
So graph (0, –7). Step 4 Draw a line connecting the points.
1 rise
Step 2 The slope is 0.5 or run
2
From (0, –7), move up 1 unit and right
2 units. Draw a dot.
5x + 4y = 8
Step 3 Draw a line through the points.

y = 0.5x – 7

Graph 5x + 4y = 8.
5
Step 1 Answer y = – x + 2
4
Solve for y to write the equation in slope- intercept
form.

5x + 4y = 8 Original equation

5x + 4y – 5x = 8 – 5x Subtract 5x from each side.

4y = 8 – 5x Simplify.

4y = –5x + 8 8 – 5x = 8 + (–5x)
or –5x + 8

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