-0.02t+(8.1-7)=20+8.1-0.42t
– 0.02t + 8.1 – 7 = 20 + 8.1 – 0.42t
– 0,02t + 0,42t = 8,1 + 20 + 7 – 8,1
0.4t = 27
t = 67.5
-0.02t+(8.1-7)=20+8.1-0.42t
– 0.02t + 8.1 – 7 = 20 + 8.1 – 0.42t
– 0,02t + 0,42t = 8,1 + 20 + 7 – 8,1
0.4t = 27
t = 67.5