(5(13/11) + 4(-19/11) = 65/11 - 76/11 = -11/11 = -1) ✔️

(3(13/11) - 2(-19/11) = 39/11 + 38/11 = 77/11 = 7) ✔️

Directly use the equivalence (1\ \textkW·h=3.6\times10^6\ \textJ); multiply by 5.6.