Question

数学六年级？

在线求挺急的！！！！

Answer 1

· 当 x ≤ -1 时
y = -(x + 1) - (x - 3) - (x - 5) = -3x + 7
ymin = y(x = -1) = 10
· 当 -1 ≤ x ≤ 3 时
y = (x + 1) - (x - 3) - (x - 5) = -x + 9
ymin = y(x = 3) = 6
· 当 3 ≤ x ≤ 5 时
y = (x + 1) + (x - 3) - (x - 5) = x + 3
ymin = y(x = 3) = 6
· 当 x ≥ 5 时
y = (x + 1) + (x - 3) + (x - 5) = 3x - 7
ymin = y(x = 5) = 8
综上所述 ymin = 6