Question 1024558
Call the number of spiders and cockroaches, s and c.  Then we write
8s + 6c = 88
s + c = 12
Now multiply the bottom one by 8 and subtract it...we get
8s + 6c = 88
-(8s + 8c = 96)
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-2c = -8
c = 4 cockroaches
s = 8 spiders