Oplossing week 12

\( \eqalign{ & a = \frac{{1 - - 8}} {{13 - 19}} = \frac{9} {{ - 6}} = - 1\frac{1} {2} \cr & y = - 1\frac{1} {2}\left( {x - 9} \right) + c \cr & 1 = - 1\frac{1} {2}\left( {13 - 9} \right) + c \cr & c = 7 \cr} \)