How does the idea of a reference triangle allow us to extend right triangle trigonometry to angles greater than 90 degrees?

i believe that the slope of the line is -5

step-by-step explanation:

answer: hence, function will be

explanation:

since we have given that

cost of a new textbook = $85

according to question, the resale value of a textbook decreases by 25% with each previous owner,

so, our function becomes,

here, y is the total value of the text book after x owners.

hence, function will be