[填空题]
The subscription fee for an online pk6v2 i h ,qg+4m(lusburoject management software by AB-Tech is 40tswk-vs cqmy: i4*lz.a b/;k2 dollars per month. If the customer buys for a whole year in advancek .2vqi-4l/; *tkscw: z mbsay, a discount of 130 dollars is applied.
This can be modelled by the following function, P(n), which gives the total cost when paying annually for the subscription.
P(n)=40n−130,n≥12where n is the number months.
1.Find the total cost of buying a subscription for 2 years. P = dollars
2.Find $P^{−1}$(1790). months
The subscription price for a different online project management tool by YZ-tech is 35 dollars per month, however customers can only purchase annually in advance, and there are no discounts. The total subscription cost of YZ-tech's software is less than AB-tech's software when n>k .
3.Find the minimum value of k.