SOLUTION: Can someone help me with this question? In 1995 the United States recovered 23% of its municipal solid wastes through recycling, up from 17% in 1990. Find an equation for the li

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Question 207958: Can someone help me with this question?
In 1995 the United States recovered 23% of its municipal solid wastes through recycling, up from 17% in 1990. Find an equation for the line whose graph depicts this data (where x is measured in years after 1990).
Answer by Theo(13342) (Show Source):
You can put this solution on YOUR website!
in 1995 23% was recovered.
in 1990 17% was recovered.
let z = the year
let x = z - 1990
this means that if z is 1990, x = 0
this also means that if z is 1995, x = 5
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let y = % recovered.
on a graph we would plot y from x.
our 2 points of consideration are:
(0,17) and (5,23)
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equation for a straight line is y = mx + b where m is the slope and b is the y intercept.
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the y intercept is the value of y when x = 0 which will be 17.
the slope is given by the formula y2-y1 / x2 - x1
x1,y1 = 0,17
x2,y2 = 5,23
y2-y1 = 23 - 17 = 6
x2 x1 = 5 - 0 = 5
out slope is 6/5
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straight line equation becomes y = 6/5 * x + 17
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graph of this equation looks like this: