Question

A restaurant charges $10 for a buffet meal plus $1 for every drink. The total cost of a meal with drinks is given by the function f(x) = x + 10. How will the graph of this function change if the price of the meal is reduced to $8 and the cost of a drink is increased by $1.25?

Answer 1

Well if you look at the equation. y = x + 10, we know the y intercept is (0,10). So if you change it to y = x + 8, it becomes (0,8).

you could also write y = x + 10 as y = 1x + 10, where 1 represents the cost of the drink. So changing price of drink would make the equation y = 1.25x + 8.

1.25 is not only the cost of the drink. It is also the slope of the graph. when a slope is changed, the graph is slightly rotated around it's y intercept.

therefore the answer is the third one