Simplify. Write "undefined" for expressions that are undefined. I don't understand it, can someone help?

Idon’t understand this.. will someone ? will mark brainliest along with 20 points.

Jose predicted that he would sell 48 umbrellas. he actually sold 72 umbrellas. what are the values of a and b in the table below? round to the nearest tenth if necessary

The length of a shadow of the building is 36m. the length of the pole, which is perpendicular to the ground, is 1.9m. the length of the pole's shadow is 1.52m. what is the height of the building?