Determinants

Question

Without expanding, prove that

$open vertical bar table row 9 cell space space space space 9 end cell cell space space 12 end cell row 1 cell space space minus 3 end cell cell space space minus 4 end cell row 1 cell space space space space 9 end cell cell space space 12 end cell end table close vertical bar space equals 0 space$

Solution

Syntax error from line 1 column 2953 to line 1 column 2958. Unexpected '<sub>'.