Todd orders pictures from a photographer. Each picture costs $7.50. A one-time
shipping fee of $3.25 is added to the cost of the order. The total cost of Tood's orde
before tax is $85.75. How many pictures did Todd order?

I think it is 12 because 7.50 ×12 is 82.5

step-by-step explanation:

1 number

if we use a graphing calculator, there is only one such number that satisfies the conclusion of the mean value theorem, that is, a number such that

where the right-hand side is the average rate of change of f on the interval [0.5,0.75], which is the slope of the secant line.

in the attached graph, the black line is the secant line which has its slope as the average rate of change of f on [0.5,0.75], while the orange line is the only tangent line to the graph of f in the interval that satisfies the mvt conclusion.