I forgot what to do
- Thread starter lilbit
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pka
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The line through \(\displaystyle (x_1,y_1)~\&~(x_2,y_2)\) is \(\displaystyle (y-y_1)=\dfrac{y_2-y_1}{x_2-x_1}(x-x_1)\)Find the equation of the line through the points (-5,2) (4,-3). Please anyone who can help
TiaharaJBennett
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That's slope, correct?
I think its called the point slope form
mmm4444bot
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What is the meaning of the pronoun "that" above?
If you are trying to ask whether the equation posted by PKA represents slope, the answer is no.
Otherwise, please explain the unreferenced pronoun.
:idea: Math discussions require clear communication.
HallsofIvy
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Another way to do this is to recall that any (non-vertical) line can be written in the form y= ax+ b. Put the x and y for those two points into that equation to get two equations to solve for a and b. Here, that gives 2= a(-5)+ b and -3= a(4)+ b. Subtracting the first equation from the second gives -3- 2= a(4- (-5))+ b- b or -5= 9a. b has been eliminated and a= -5/9.Find the equation of the line through the points (-5,2) (4,-3). Please anyone who can help
Notice that the calulation for a, (-3-2)/(4- (-5)), is exactly what pka gave for the slope. You can now put a= -5/9 back into either 2= a(-5)+ b or -3= a(4)+ b and solve for b.
(A line would be vertical if the two x coordinates were the same as in (3, 2), (3, -3). Then the equation is x= 3.)