Return true if three line are concurrent , else false .
def checkConcurrent ( a1 , b1 , c1 , a2 , b2 , c2 , a3 , b3 , c3 ) : NEW_LINE INDENT return ( a3 * ( b1 * c2 - b2 * c1 ) + b3 * ( c1 * a2 - c2 * a1 ) + c3 * ( a1 * b2 - a2 * b1 ) == 0 ) NEW_LINE DEDENT