use a matrix to solve each system

Question

2x + 7y +2z = -16
-5x - 8y = 17
x - 2y - 8z = -13

Answer 1

Look here:

https://www.wolframalpha.com/input/?i=%7B%7B2%2C7%2C2%7D%2C%7B-5%2C-9%2C0%7D%2C%7B1%2C-2%2C-8%7D%7D*%7B%7Bx%7D%2C%7By%7D%2C%7Bz%7D%7D+%3D+%7B%7B-16%7D%2C%7B17%7D%2C%7B-13%7D%7D

To do it by hand, you'll need the inverse matrix here:

https://www.wolframalpha.com/input/?i=inverse+%7B%7B2%2C7%2C2%7D%2C%7B-5%2C-9%2C0%7D%2C%7B1%2C-2%2C-8%7D%7D