Question 161268
8n+2-10n<20 
-2N<20-2
-2N<18
N>18/-2 THE SIGN CGHANGES WHEN YOU DIVIDE BY A NEGATIVE VALUE.
N>-9 ANSWER.
PROOF:
LET N=-8
8*-8+2-10*-8<20
-64+2+80<20
82-64<20
18<20
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5-4m+8+2m>-17 
-2M>-17-5-8
-2M>-30
M<-30/-2
M<15
PROOF:
LET M=14
5-4*14+8+2*14>-17
5-56+8+28>-17
41-56>-17
-15>-17
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i'LL LEAVE THE LAST ONE FOR YOU TO PRACTICE WITH.
2x-3/5<7