Question

Determine o valor de m de tal forma que A(3-,7) , B(m,m) e C(3,-2) , sejam colineares.

Answer 1

$\left|\begin{array}{cccc}3&m&3&3\\-7&m&-2&-7\\\end{array}\right|=0 \\ \\ |3.m+m(-2)+3(-7)-[-7.m)+m.3-2.3]=0 \\ \\ |3m -2m-21+7m-3m+6|=0 \\ \\ |5m-15|=0 \\ \\ 5m-15=0 \\ \\ 5m=15 \\ \\ m=3$