The point of intersection of the lines and is . Use a matrix method to find .
Since the intersection point is (2,1), its matrix representation would be , it follows that and
However, if I solve the first equation for a, I get , but when I solve the second equation for a, I get ....
Did you copy the intersection pt correctly?
The problem is that the second line doesn't even pass through the point of intersection!
Basically I think the second equation should be and then as far as I can see a=7 is the answer, which makes sense given that if you plug (2,1) into the first line equation you get ... 7. No real need for matrices here I fear...