SOLUTION: Find the shortest distance from the given point (-3,0) to the given line x-y=-10

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Question 1137656: Find the shortest distance from the given point (-3,0) to the given line x-y=-10
Answer by ikleyn(52790) About Me  (Show Source):
You can put this solution on YOUR website!
.

You want to find the distance from the point (-3,0) to the given straight line  x - y + 10 = 0.


There is a remarkable formula which ideally suits for this need.


    Let the straight line in a coordinate plane is defined in terms of its linear equation 

         a*x + b*y + c = 0,

    where "a", "b" and "c" are real numbers, and let P = (x%5B0%5D,y%5B0%5D) be the point in the coordinate plane. 

    Then the distance from the point P to the straight line is equal to

        d = abs%28a%2Ax%5B0%5D+%2B+b%2Ay%5B0%5D+%2B+c%29%2Fsqrt%28a%5E2+%2B+b%5E2%29.


Regarding this formula, see the lesson
    The distance from a point to a straight line in a coordinate plane
in this site.


Substitute the given data  a= 1, b= -1, c= 10,  x%5B0%5D = -3,  y%5B0%5D= 0  into the formula to get the distance under the question


    abs%281%2A%28-3%29+%2B+%28-1%29%2A0+%2B+10%29%2Fsqrt%281%5E2%2B%28-1%29%5E2%29 = 7%2Fsqrt%282%29 = %287%2Asqrt%282%29%29%2F2 = 4.95 units  (approximately).


Answer.  The distance under the question is 4.95 units  (approximately).

Solved.