Three years ago, my father's age was five times that of Xiaoli. Five years later, my father's age is three times that of Xiaoli. How old is Xiaoli this year? I want the process of arithmetic! Besides, I don't know the quadratic equation of two variables!

Let Xiao Li be x years old three years ago and her father be 5x years old
3*（x+3+5）=5x+3+5
3x+24=5x+8
2x=24-8
x=8
3 + 8 = 11 years old

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