Writing Equations in Slope-Intercept Form
Write in slope-intercept form
(4,3) (0,-3)
y=(3/2)x-3
Write in point-slope form:
(1,-4), m=-2
y+4=-2(x-1)
Write an equation in standard form:
(1, 1)
(2, -2)
3x + y = 4
Write an equation that is parallel to y=2x+3 and passes through the point (5, -4).
y=2x - 14
Describe the relationship of the data.
0
0 0 00
0 0
00 0 0
0 0 0
0
Negative linear correlation
Write in slope-intercept form
(-3,5) (3,-7)
y=-2x-1
Write in point-slope form:
(-8, 3), m=1/4
y-3=1/4(x+8)
Write an equation in standard form:
y + 1 = -1/4(x - 3)
1/4x + y = -1/4
or
x + 4y = -1
Write an equation of a line that is perpendicular to y=(1/2)x + 3 and passes through the point (-3, 1).
y= -2x - 5
SURPRISE!
You deposit $125 into an account that earns 4% simple interest. How much will be in the account after 3 years?
$140
Write a linear function.
f(0)=10, f(6)=34
f(x)=4x+10
Write in point-slope form:
(-2, -5), m=3
y+5=3(x+2)
Write an equation in standard form:
y - 2 = 1/3 (x - 3)
-1/3x + y = 1
or
-x + 3y = 3
y= (-1/4)x - 2
Interpret the strength and direction of the correlation.
Lemonade Stands
(x-axis: temperature outside, y-axis: # of lemonade stands)
x x
x x x
x
x x
x x x
x x
x x
If you were to draw a line of fit, the residuals would be relatively small, you can conclude that there is a strong, positive correlation.
So, as the temperature outside increases, the number of lemonade stands generally increases.