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Teach me the equation of degree 2, Specific application questions, examples. Besides substituting elimination method?
Dogtail grass,
There are 15 adults and children going to a concert. The tickets are 5 yuan for adults and 3 yuan for children. The total amount of tickets is 65 yuan. How many adults and children are there?
There are x adults and y children in the solution. According to the meaning of the question, there are x + y = 15 ①, 5x + 3Y = 65 ②, ① * 5 - ②, 2Y = 75-65, y = 5, substituting ①, x = 10
Who can tell me what to do with the equation of degree 1 with 2 variables
Such as this question
（1）[X=﹣7
3y＋1=2
（2）{X＋2y=7
3y＋1=2
{x=-7
y=1/3
（2）
{x=19/3
y=1/3
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