Question 608560: I am tutoring my granddaughter and I am stuck. We have our known x and y numbers and need to write the formula to express them.
For the following sets of points, what is the equation: X=0, Y=5...X=1, Y=2...X=2, Y=-1...x=2, y=-1, and x=3, Y=4. I can see that x is increasing by 1 and y is decreasing by 3, but for the live of me I can't figure out how to write the formula.
For the following sets of points, what is the equation: x=-2, y=1 ... x=0, y=0,... x=2, y=-1, ,and x=4, y=-2. x is increasing by 2, y is decreasing by 1.
Thanks
Candy
candace_rolsky@wowway.com
Answer by ewatrrr(24785)   (Show Source):
You can put this solution on YOUR website!
Hi
Using the standard slope-intercept form for an equation of a line:  , where m is the slope and b the y-intercept.
X=0, Y=5...X=1, Y=2...X=2, Y=-1
(1,2)
(0,5) m = -3/1 = -3, |Yes, x is increasing by 1 and y is decreasing by 3
y = -3x + b
5 = -3·0 + b
5 = b
 Green
x=2, y=-1, and x=3, Y=4.
(3, 4)
(2, -1) m = -5/-1 = 5
y = 5x + b
-1 = 5·2 + b
-11 = b
 Blue
x=-2, y=1 ... x=0, y=0,...
(0, 0)
(-2, 1) m = -1/2 |Yes, x is increasing by 2, y is decreasing by 1
y = (-1/2)x + b
0 = (-1/2)0 + b, b = 0
y =  Purple (Note: with negative slopes, lines slant to the left)
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