Answer:i) = 23 °Cii) = 4.4° CStep-by-step explanation:i) The temperature on the surface of the planet.At the surface of the planet the height is ZeroTherefore, X = 0Thus; using the equation, the temperature, y will be;y = 23 - 5xy = 23 - 5(0) = 23 °Cii) the temperature change for every kilometer from the surface,From the equation;y = 23 - 5xwe take, y to be 1 Therefore;1 = 23 -5x , subtracting 23 on both sides we get -22 = -5xx = -22/-5 = 4.4° C