What is another name for an indirect proof? picture included

Yo y do yall have 2 stars that means yall wrong bro

Agreeting card company can produce a box of cards for $7.50. if the initial investment by the company was $50,000, how many boxes of cards must be produced before the average cost per box falls to $10.50?

If the measure of angle 1 is 110 degrees and the measure of angle 3 is (2 x+10 degree), what is the value of x?