Question

Se $\left[\begin{array}{ccc}x&y\\m&n&\\&&\end{array}\right] . \left[\begin{array}{ccc}2&\\4\\\end{array}\right] = \left[\begin{array}{ccc}0&\\0\\\end{array}\right]$ então, necessariamente;
a)x=y=0
b)x=y=m=n=0
c)x=y e m=n
d)y= -2x e n= -2m
e)x= -2y e m= -2n

Answer 1

Ola Dâmari

(x   y) (2) (0)
(m  n) (4) (0) 

2x + 4y = 0
2m + 4n = 0

2x = -4y
x = -2y

2m = -4n
m = -2n 

letra (E)

.