linear algebra: cofactor expansion (determinants)?

Let T be the triangle with vertices (3, 3), (-1, -1), (4, 1). Find the coordinates of the vertices of the image of T under the matrix transformation with matrix representation A=[4 -3; -4 2].

answer: (3, -6), (-1, 2), (13, -14)

How are you supposed to solve this? Can someone help me please?

Question

linear algebra: cofactor expansion (determinants)?

Let T be the triangle with vertices (3, 3), (-1, -1), (4, 1). Find the coordinates of the vertices of the image of T under the matrix transformation with matrix representation A=[4 -3; -4 2].

answer: (3, -6), (-1, 2), (13, -14)

How are you supposed to solve this? Can someone help me please?

anonymous · Answer

If I'm not mistaken, you're supposed to multiply the matrix A by each vertex of the triangle (in column form), and generate the image that way. It's hard to definitely know what the question's asking without knowing how it's represented in terms of matrices and vectors, but I think that's how you do it. Let me double-check the answer with my method.

anonymous · Answer

Yeah, it checks out.

he66666 · Answer

Thanks @QuantumModulus ! It worked :)

anonymous · Answer

Glad I could help. ^_^