Question

The following two vectors satisfy the same system of linear equations. u=⎡⎣⎢⎢6−5−5⎤⎦⎥⎥, v=⎡⎣⎢⎢746⎤⎦⎥⎥ Find x and y that make the vector ⎡⎣⎢⎢3xy⎤⎦⎥⎥ a solution to the corresponding homogeneous system:

Answer 1

Answer:

x=-30/71, y=0

Step-by-step explanation:

if a vector satisfies an equation of the form ax+by+cz=0 then the vector is  

parallel to the plane ax+by+cz=0, and, the cross product of two vectors results in an orthogonal vector to both.

So, <a,b,c> the normal vector of the plane ax+by+cz=0, can be found as the cross product of the two parallel vetors to the plane:

<a,b,c> = <6,-5,-5>×<7,4,6>= <-10,-71,59>

so, the homogeneous system is:

-10x-71y+59z=0

by replacing the vector <3,x,y> in the system

-30-71x+59y=0

So, there are 2 unknown variables and 1 equation, it means that 1 variable is free

so, y=0 is a random defition and x can be obtain with the equation

-30-71x=0 -> x=-30/71