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For a certain value of k, the system

 

3a + 4b = 7,

6a + 4b = k - 3a - 8b

 

has infinitely many solutions (a,b). What is k?

 Jul 9, 2021
 #1
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3a  +  4b    =   7   ⇒  multiply through by 3 ⇒    9a  + 12b  = 21

6a  +  4b  =  k  - 3a   - 8b ⇒ simplify ⇒               9a + 12b  =  k

 

k = 21

 

cool cool cool

 Jul 9, 2021

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