x^2-y^2=31,x,y为正整数,求x,y的值
问题描述：
x^2-y^2=31,x,y为正整数,求x,y的值
答
x^2 - y^2 = 31
(x + y)(x - y) = 31 = 31 * 1
因为31是质数,只能分解为31 * 1.而x,y为正整数,所以有:
x + y = 31
x - y = 1
则
x = 16
y = 15