Respuesta :

JessicaRufus
Simplify c+2c+12 to 3c+12
3c+12=75
Subtract 12 from both sides
3c=75−12
Simplify 75−12 to 63
3c=63
Divide both sides by 3
c=63/3
Simplify 63/3 to 21
c=21
Albina
c+2c+12=75
3c + 12 = 75
3c = 75 - 12
3c = 63
с = 63 : 3
с = 21
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3 × 21 + 12 = 75
      63 + 12 = 75
              75 = 75