[填空题]
The subscription fee for an oy5 ,7w d;t cjctq;o bu5ysxbw apj,122nline dau59 owq6bv r(8*3p xnma )qy0jeq z0project management software by AB-Tech is $40$40 per month. If the customer buys for a whole year in advance, a discount of $130$130 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). $P^{-1}$ = months
The subscription price for a different online project management tool by YZ-tech is 35dollars 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. k =
