The link leads to a single table, and that table doesn't show [ y = 18x ].
You're looking for a table in which each 'y'-value is
18 times the 'x'-value that's right next to it.
Good luck in your quest.
To do this, multiply each of the four elements in matrix D by -1/2 or -0.5:
| 9 8 |
| -7 -4 |
X-12 +5x=90
That’s the set up
Let me know if you need more help