Question 764747: define variables and write an equation to model the relationship in the table
payment change
$1 $9
$2 $8
$3 $7
Answer by MathLover1(20850)   (Show Source):
You can put this solution on YOUR website! payment change
$ $
$ $
$ $
if payment represents  and change  , we have points ( ,),( ,),(,) that should lie on same line; so, we can fine a line passing through two points:
| Solved by pluggable solver: Find the equation of line going through points |
hahaWe are trying to find equation of form y=ax+b, where a is slope, and b is intercept, which passes through points (x1, y1) = (1, 9) and (x2, y2) = (2, 8).
Slope a is  .
Intercept is found from equation  , or  . From that,
intercept b is  , or  .
y=(-1)x + (10)
Your graph:
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so, equation is 
now we can check if all three points lie on this line:
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