Question

a+b=38,b+c=55,a+c=41. Calculati 3×(a+b+c)

Answer 1

2a+2b+2c=38+55+41deci 2(a+b+c)=134 deci a+b+c=134:2=67 deci 3*(a+b+c)=67*3=201

Answer 2

a+b=38
b+c=55
a+c=41
3*(a+b+c)=?
(a+b)+(b+c)+(a+c) = 2(a+b+c) = 2 (38+55+41) = 2* 134 = 268
2(a+b+c) = 268 => a+b+c=268:2=134
3*(a+b+c)=3*134=402
R: 402