from the first:
y = -458 - 8x
plug that into the second:
-5x + 3y = 221
-5x + 3(-458-8x) = 221
I will let you finish it,
once you find x, don't forget to find y from y = -458-8x
use substitution to solve this linear system:
8x + y = -458
-5x + 3y = 221
2 answers
x=39.8