SOLUTION: Graph the line containing the given pair of points and find the slope. (2,4), (-1,-2) Can someone please help me with this, yes I am taking Algebra again and need some serious

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: Graph the line containing the given pair of points and find the slope. (2,4), (-1,-2) Can someone please help me with this, yes I am taking Algebra again and need some serious       Log On


   



Question 134283: Graph the line containing the given pair of points and find the slope.
(2,4), (-1,-2)
Can someone please help me with this, yes I am taking Algebra again and need some serious help with some things, if someone can help I would much appreciate it.

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
First lets find the slope through the points (2,4) and (-1,-2)

m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29 Start with the slope formula (note: is the first point (2,4) and is the second point (-1,-2))

m=%28-2-4%29%2F%28-1-2%29 Plug in y%5B2%5D=-2,y%5B1%5D=4,x%5B2%5D=-1,x%5B1%5D=2 (these are the coordinates of given points)

m=+-6%2F-3 Subtract the terms in the numerator -2-4 to get -6. Subtract the terms in the denominator -1-2 to get -3


m=2 Reduce

So the slope is
m=2

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Now let's use the point-slope formula to find the equation of the line:



------Point-Slope Formula------
y-y%5B1%5D=m%28x-x%5B1%5D%29 where m is the slope, and is one of the given points

So lets use the Point-Slope Formula to find the equation of the line

y-4=%282%29%28x-2%29 Plug in m=2, x%5B1%5D=2, and y%5B1%5D=4 (these values are given)


y-4=2x%2B%282%29%28-2%29 Distribute 2

y-4=2x-4 Multiply 2 and -2 to get -4

y=2x-4%2B4 Add 4 to both sides to isolate y

y=2x%2B0 Combine like terms -4 and 4 to get 0

y=2x Remove the zero terms


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Answer:


So the equation of the line which goes through the points (2,4) and (-1,-2) is:y=2x

The equation is now in y=mx%2Bb form (which is slope-intercept form) where the slope is m=2 and the y-intercept is b=0

Notice if we graph the equation y=2x and plot the points (2,4) and (-1,-2), we get this: (note: if you need help with graphing, check out this solver)

Graph of y=2x through the points (2,4) and (-1,-2)

Notice how the two points lie on the line. This graphically verifies our answer.