Solving Vector Multiplication (general problem) [closed]

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I am trying to solve a Mathematical equation in one of my geometric modelling problem.

Let's say if I have 2 vectors, A and B, and I have the following equation:

A x B = c (c is a scalar value).

If I know the coordinate of my vector B (7/2, 15/2); and I know the value of c, which is -4. How can I calculate my vector A, to satisfy that equation (A X B = c) ?

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The problem is underdetermined; there isn't a unique such A. I assume that by "multiplication" you mean the cross product.

A = (x,y)
B = (7/2, 15/2)
A×B = x(15/2) - y(7/2)
-4 = (15x-7y)/2
15x - 7y = -8

This gives a line along which points A=(x,y) can lie. Specifically, for any real number t,

x = -1 + 7t
y = -1 + 15t

gives a solution.