Please help me solve this problem

Awall is 20 cm thick. At the outside, the temperature is 3C, and at the inside, it is 21C. If the temperature changes at a constant rate through the wall, write an equation of the temperature T in the wall as a function of the distance x from the outside to a point inside the well, What is the meaning of the slope of the line? (I) Ttxi = (Simplify your answer. Do not factor. Use integers or fractions for any numbers in the expressions) What is the meaning of the slope of the line? Select the correct choice below and fill in the answer box within your choice. (Type an integer or a simplified fraction.) 0 A- The temperature increases by C for each increase of 1 cm in the distance from the outside edge of the walls 0 5- The distance from the outside edge of the wall increases by cm for each increase of 1C in the temperature