Matlab's backslash operator \ seemingly acts as a matrix inverse then multiply operator. So I often read:
x = A\b
as x = A-1 b. Indeed,
help \
reveals in matlab's documentation:
A\B is the matrix division of A into B, which is roughly the same as INV(A)*B, except it is computed in a different way.
This is very misleading when you consider:
x = 2*A\b;
If A=1;b=1; then this sets x to 0.5! This is because \ as a division operator does not take precedence over *, and because it comes later in the expression this is equivalent to:
x = (2*A)\b;
which---so long as A is invertible--- is equivalent to:
x = 0.5*(A\b);
but decidedly not equivalent to:
x = 2*inv(A)*b;
or
x = 2*A^-1*b;
which both set x to 2.