What methods are useful to create the equation of a line?

Ivan and jeff buy a package of 8 pens for $4.00. ivan wants 5 of the pens, and jeff wants 3.how much should each student pay?

Sanjay solved the equation below. which property did he use to determine that 7x+42=42 is equivalent to 7(x+6)=42 7x+42=42 7x=0 x=0

Aladder that is 20 ft. long against the side of a building. f the angle formed between the ladder and the ground is 75 degrees, how far is the bottom of the ladder from the base of the building?