SOLUTION: A line contains (-4,y) and (2,4y).It has a slope 2/3,Find Y?

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Question 722873: A line contains (-4,y) and (2,4y).It has a
slope 2/3,Find Y?
Found 2 solutions by solver91311, MathLover1:
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


Use the slope formula:



where and are the coordinates of the given points. Set and solve for

John

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Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!
given:
a line contains (-4,y) and (2,4y)
it has a slope m=2%2F3

slope intercept form:
y=mx%2Bb.......for (-4,y)

y=%282%2F3%29%28-4%29%2Bb.......eq.1
y=mx%2Bb.......for (2,4y)
4y=%282%2F3%292%2Bb.......eq.2
_____________________.......solve this system
y=%282%2F3%29%28-4%29%2Bb.......eq.1
4y=%282%2F3%292%2Bb.......eq.2
______________________________subtract eq.1 from eq.2
4y-y=%282%2F3%292%2Bb-%282%2F3%29%28-4%29-b
3y=%282%2F3%29%282-%28-4%29%29
3y=%282%2F3%29%282%2B4%29
3y=%282%2F3%296
3y=%282%2Fcross%283%29%29cross%286%292
3y=2%2A2
3y=4
y=4%2F3
now we can find b

4%2F3=%282%2F3%29%28-4%29%2Bb.......eq.1
4%2F3=-8%2F3%2Bb
4%2F3%2B8%2F3=b
12%2F3=b
4=b
so, the line y=%282%2F3%29x%2B4 should contain given points (-4,y)= (-4,4%2F3) and (2,4y)=(2,4%284%2F3%29=16%2F3)
or (-4,1.3) and (2,5.3)