A tourist goods dealership buys two kinds of souvenirs, A and B. If 38 yuan is used to buy 7 pieces of A and 8 pieces of B; You can also buy 1 pieces of a type and 6 pieces of b type, and ask for it.

problem 1: the quadratic equation of one variable can be solved. The equation is 7A+8B=38 1A+6B=38, so A=2; B=3

Question 2: According to the two conditions that the purchase price does not exceed 9 and the quantity of A and B souvenirs is 4, it can be known that the definition domain of A and B souvenirs is 3≤A≤4; ≤B≤1; Then the maximum profit can be obtained according to the maximum value of the profit equation (let profit be N)N=5A+7B in the domain of A and B. In fact, because B souvenirs have a higher profit, simply speaking, after meeting the minimum quantity of A of 3 (which is the minimum value of A with a price not exceeding 9), the more B souvenirs are purchased, the more profits will be made, so: A purchases 3 pieces, and B purchases 1 pieces, and the total profit is the largest; The maximum profit is: 22 yuan.

216 yuan is a meaningless number.

I hope it helps you.