Matematică
erwq25
2018-07-09 21:20:42
Stiind ca a+b+c=192,b-c=123,2a+b+3c=?
Răspunsuri la întrebare
chiraumihaela17
2018-07-10 00:13:26

a+b+c=192   +     b-c=123 __________ a+2b =192+123 a+2b= 315 2a+b+3c= 2a +4b- 3b+3c= 2*(a+2b)-3*(b-c)= 2*315 - 3*123=630-369= 261

adelinadela
2018-07-10 00:14:41

a+b+c=192      b-c=123 se aduna ambele ecuatii a+b+c+b-c=192+123 a+2b= 315 2a+b+3c= se desface in :  2a +4b- 3b+3c=  (a+2b)+(a+2b)-3×(b-c)= 315+315 -3×123=630-369= 261 2a+b+3c=261

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