SOLUTION: Write the equation of the line K that passes through the points (4,9) and (-1,-1).

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Question 1130468: Write the equation of the line K that passes through the points (4,9) and (-1,-1).
Found 2 solutions by josgarithmetic, ikleyn:
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
Equation of the line passing through points (h,k) and (p,v):

The points (x,y) for which
These two slopes are equal -----

%28v-k%29%2F%28p-h%29=%28y-x%29%2F%28x-h%29

y-k=%28%28v-k%29%2F%28p-h%29%29%28x-h%29

y=k=%28%28v-k%29%2F%28p-h%29%29x-%28%28v-k%29%2F%28p-h%29%29h

highlight%28y=%28%28v-k%29%2F%28p-h%29%29x%2Bk-%28%28v-k%29%2F%28p-h%29%29h%29

---
Using your given points,
slope, %289-%28-1%29%29%2F%284-%28-1%29%29=2

%28y-%28-1%29%29%2F%28x-%28-1%29%29=2, here some of the computations already done

%28y%2B1%29%2F%28x%2B1%29=2

y%2B1=2%28x%2B1%29, about the same as typical point-slope form

y=2x%2B2-1

highlight%28y=2x%2B1%29

Answer by ikleyn(52805) About Me  (Show Source):
You can put this solution on YOUR website!
.
First find the slope  m = %28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29 = %28%28-1%29-9%29%2F%28%28-1%29-4%29%29 = %28-10%29%2F%28-5%29 = 2.


Now an equation of the line is


    y-9 = 2*(x-4),   or


    y - 9 = 2x - 8,

    y = 2x - 8 + 9,

    y = 2x + 1.      YOUR FINAL ANSWER

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