I dont understand this.

Mp model with mathematics explain how the number of text messages dario sent and the cost form an arithmetic sequence. then write an expression to find dario's text messaging bill if he sends n text messages over 250.

Consider a graph for the equation y= -3x+4. what is the y intercept? a) 4 b) -4 c) 3 d) -3

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?