A is not a line of symmetry
X is equal to 8. The work for that is on the attached picture.
1/8 is the answer to the problem
The vector AB is found by subtracting the coordinates of point B from the coordinates of point A => (8, 3, 4) - (5, 7, - 2)
(8, 3, 4) - (5, 7, - 2) = (3, - 4, 6)
=>
a) a 3 x 1 column =
| 3 |
| -4 |
| 6 |
b) xi + yj + zk
=> 3i - 4j + 6k
1 and 2 I hope this help you :)