若a^2-2a+1的算术平方根是2a-3,则a等于多少?
问题描述:
若a^2-2a+1的算术平方根是2a-3,则a等于多少?
答
a² - 2a + 1 = (2a - 3)²
(a - 1)² = (2a - 3)
(2a - 3 + a - 1)(2a - 3 -a + 1) = 0
(3a - 4)(a - 2) = 0
a = 4/3 或 a = 2
当 a = 4/3 时 2a - 3 = -1/3 当 a = 2 时 2a - 3 = 1
综上:a = 2