+0  
 
+1
130
2
avatar+190 

what is the sum of all integers n that satisfy -3n<7n-20<3n

 Feb 10, 2020
 #1
avatar+111389 
+1

 -3n<7n-20<3n

 

We can split this into two parts

 

-3n < 7n - 20                                    7n - 20  <  3n

              subtract 7n from both sides

 

-10n <  - 20                                   -20  <  - 4n

 

divide both sides by -10                divide both sides by  -4

 

Becuse we are dividing both sides by a negative, reverse the inequality signs

 

n > 2                                               5  >  n

 

n > 2                   and                        n  <  5

 

So....the solution is

 

2  < n   <   5

 

So....the sum of the integers that satisfy this   is

 

3 +  4   =    

 

7

 

cool cool cool

 Feb 10, 2020
 #2
avatar+190 
+1

thank you CPhill

notsmart2.0  Feb 10, 2020

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