Download Algebra 1 6.2 ‐ slope intercept form A. Linear Equations • Linear

Algebra 1
6.2 ‐ slope intercept form
Linear Equations
A.
Linear Equations ‐ an equation whose graph is a line
•
In linear equations, the x and/or y coordinate has degree 1
•
This means that the exponent on x and/or y is 1
•
Not all equations are linear. Below are some examples and non‐
•
examples of linear equations.
Non‐Examples
Examples
y = x2, y = x3 ‐ 8 y + x = 2
f(x) = 2x ‐ 6
x = 7
y = 3
f(x) = ½x ‐ 2 Jan 19­1:57 PM
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Intercepts ‐ the point at which the graph crosses the axes. •
y‐intercept ‐ place where the graph crosses the y‐axis given by the •
ordered pair (0, y). x‐intercept ‐ place where the graph crosses the x‐axis given by the •
ordered pair (x, 0).
Find the x and y intercepts of the following.
1. 2x + 3y = 12
2. 4x ‐ y = 8
Jan 19­4:09 PM
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B. Slope Intercept Form
Slope Intercept Form ‐ an equation of a line written in the form y = mx + b •
where m is the slope and b is the y‐intercept. m, the slope is the coefficient on x, or the number that is being multiplied •
by x
since b is the y‐intercept, the ordered pair that crosses the y‐axis for that •
point is (0, b)
Jan 19­4:14 PM
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C. Examples. Find the slope and y‐intercept of the following
1. y = ‐3x + 6
2. y = ½x ‐ 5
3. y = ‐0.4x ‐ 2.8
4. 2x + 3y = 9
Jan 19­4:20 PM
4
D. Write the equation of the line with the given slope and y‐intercept
5. m = 2/5 and b = 6
6. m = ‐3/4 and b = ‐9
7. m = ‐7/3 and b = 0
Jan 19­4:20 PM
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E. Write the slope‐intercept form of the equation for each line graphed.
8. 9.
Jan 19­4:21 PM
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F. Graph the following lines using slope and y‐intercept
11. 10. y = 3x + 5
12. Jan 19­4:25 PM
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G. Applications. 13. The base pay for a used car salesperson is $300 per week. The salesperson also earns 15% commission on sales made. (a) Write an equation to model this situation
(b) Graph the equation
Jan 19­4:30 PM
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6.2 HW p. 320 #s 2 ­ 52 even, 80 and 81
Jan 19­4:32 PM
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