bantuin no 3 dan 4 donkk

3.
12,6 Kj = 12600 j
500 g= 0,5 kg
Q = mc/\T
12600 = 0, 5 * 4200*( 80 -T)
12600 = 2100 (80-T)
(80-T)= 12600/2100
(80-T) = 6
T = 80 -6
T = 74