Does anyone know what L is? I'm trying to see if I could find videos on it on YouTube. On the first question this is what I think- [a;b] is a vector by the way: 1) [2;1]c1+[7;4]c2=[1;0] [2;1]c1+[7;4]c2=[0;1] I could have also combined those two by having the linear combination equal to a size 2 identity matrix, right?! Is this correct? 2) This is where I'm lost. I know how to switch between a standard basis and a given basis. I'm not exactly sure of the nature of the equation being asked or what it even is, including what L is.