Answer:
<em>x=-7</em>
<em>y=11</em>
Step-by-step explanation:
<u>Perpendicular Vectors</u>
Two vectors defined as their endpoints and
are perpendicular if their dot product a.b is zero. The dot product is
In other words
ac+bd=0
Let's treat all the points as the extremes of vectors, so we can easily find the missing coordinates
B (3,5) and C (7,15) define a segment, the vector
The point A is A (x,9), we need to form a vector with B
this vector must be perpendicular to BC, so, applying the dot product we have
The point D is D(17,y), we need to form a vector with C
this vector must be perpendicular to BC, so, applying the dot product we have
The points are