Answer:
x=3
y=21
Step-by-step explanation:
To use substitution method, first we need to decide which variable solve first, either x or y.
Here we decide to start by 'y' using equation y=x+18, which is already solved for 'y'
That same equation is then substitute into the first equation:
x+18= 10x-9
From here, we isolate 'x' variable and grouping terms, we have this:
27=9x
Resulting x=3
Now, we can use the above result in the second equation (y=x+18)
Leading to y=3+18=21.
