warm up… solve each equation for y. (1)y – 5 = 4x (2) y + 2x = 7 (3) 2y + 6 = -8x calculate the...
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Warm Up…Solve each equation for y.
(1)y – 5 = 4x (2) y + 2x = 7 (3) 2y + 6 = -8x
Calculate the slope given the two points.
(4) (-4, 4) and (2, -5) (5) (0, -1) and (1, -6)
#6.2 - Graphing Linear EquationsIn Slope-Intercept Form
Objective: SWBAT graph linear equations
A linear equation graph will always create a line. Linear equations are in the form y = mx + b or can be rewritten into the form y = mx + b.
In this section, instead of making a table, evaluating y for each x, plotting the points and making a line, we will use The Slope-Intercept Form of the equation to graph the line.
These equations are all in Slope-Intercept Form:
Notice that these equations are all solved for y.
Formula for Slope – Intercept Form
• ‘b’ is the y-intercept (the point where the graph crosses the y – axis)
• ‘m’ is the slope
y = mx + b
Just by looking at an equation in this form, we can draw the line (no tables).
•The constant is the y-intercept.
•The coefficient is the slope.Constant = 1, y-intercept = 1.
Coefficient = 2, slope = 2.
Constant = -4, y-intercept = -4.
Coefficient = -1, slope = -1.
Constant = -2, y-intercept = -2.
Coefficient = 3/2, slope = 3/2.
up 2
right 1 up 2
right 1
right 1down 1
right 1
down 1
right 2
up 3
right 2
up 3
y = x
y = -3 x = 2
Sometimes we must solve the equation for y before we can graph it.
The constant, b = 3 is the y-intercept.
The coefficient, m = -2 is the slope.