Li Ming needs to send a certain number of mobile phone text messages every month because of his work, so he asked his colleague Lao Wang and Xiao Zhang about the relevant charging standards. Lao Wang

Li Ming needs to send a certain number of mobile phone text messages every month because of his work, so he asked his colleague Lao Wang and Xiao Zhang about the relevant charging standards. Lao Wang said, "I" Solution: (1) y = 0.06x+8;

(2) Omit and draw correctly;

(3) Let the analytical formula of BC be y=kx+b, which is obtained by BC passing through points (100, 12) and (250, 24).

solve an equation

Therefore, the resolution function of BC is y = 0.08x+4;

(4) According to the image, when the number of short messages sent each month is less than 67 or more than 200, use the thumb card.

When the number of SMS messages sent per month exceeds 67 but not more than 200, use the Supreme Card;

(5) Line 5)AB indicates the minimum charge for the Supreme Card 12 yuan, and 100 messages are free.