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Question 59322This question is from textbook
: here's a table.
x y
4 14
8 15.5
12 17
16 18.5
i know the rate of change is 1.5, but how would i find the value of y when x=120?? how about finding the value of x when y=50??
This question is from textbook
Answer by funmath(2933) (Show Source):
You can put this solution on YOUR website! here's a table.
x y
4 14
8 15.5
12 17
16 18.5
How would i find the value of y when x=120?? how about finding the value of x when y=50??
Your rate of change is the slope between various points. I checked this out and this is indeed a linear relation.
The formula to find the slope between two points is:
You can choose any two points to find the slope, so let's choose the ones without decimals to make it a little easier.
(x1,y1)=(4,14) and (x2,y2)=(12,17)


We can now find the equation of the line using the point-slope formula: , m=slope,(x1,y1)=any point on the line.
(x1,y1)=(4,14) and m=3/8









:
When x=120
3(120)-8y=-100
360-8y=-100
-360+360-8y=-360-100
-8y=-460
-8y/-8=-460/-8
y=115/2

:
When y=50
3x-8(50)=-100
3x-400=-100
3x-400+400=400-100
3x=300
3x/3=300/3

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If I just blew your mind and you've never seen any of this before, another way you can do this is to plot the points on a graph and using graph paper and a ruler you can approximate the same thing.
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Happy Calculating!!!
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