Question 782542
   a + 8b = 8
 -(a + 3b = -2)

5b = 10
b = 2 

a + 8(2) = 8
a + 16 = 8
a = 8 -16
a = -8

check:

-8 + 8(2) = 8
-8 + 16 = 8
8 = 8

-8 + 3(2) = -2
-8 + 6 = -2 
-2 = -2