Question 1146601
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The response from the other tutor shows a detailed solution to the problem.<br>
You should be able to understand all the steps required for the solution; and you should be able to solve a similar problem by that method.<br>
However, in practice, there is a concise formula for finding the (shortest) distance from a given point to a given line.  When the equation of the line is in the form Ax+By+C=0, then the distance from a point (p,q) to the line is<br>
{{{abs((Ap+Bq+C)/sqrt(A^2+B^2))}}}<br>
In the required form, the equation in this problem is 5x+2y-4 = 0.  Then the distance from (15,-21) to that line is<br>
{{{abs((5(15)+2(-21)-4)/sqrt(5^2+2^2)) = abs(29/sqrt(29)) = abs(sqrt(29)) = sqrt(29)}}}